Monitoring Consul with statsd exporter and Prometheus

My choice for using a monitoring tool is currently Prometheus. With Prometheus you can easily gather metrics of applications and/or databases to see the actual performance of the application/database. When you have a tool like Zabbix or Nagios, you’ll need to write one or multiple scripts to gather all metrics and see how much you can store in your database without loosing performance of your monitoring tool. About the why Prometheus and not doing this with Zabbix or other monitoring tool is an subject for maybe an other blogpost.

One interesting application to monitor is Consul. When you look for monitoring Consul in google, you’ll find a lot of pages that shows you that you can use Consul as a monitoring tool but not many on how you can monitor Consul itself. With this blogpost I’ll describe what steps I have taken to monitor Consul. Please keep in mind this is is just a start and it is incomplete, so if you have suggestions to improve it please let me know.

On this blogpost we will do the following actions:

  • Configure Consul
  • Configure statsd exporter
  • Create some graphs

Configure Consul

Consul has a way for exposing metrics, called Telemetry. With Telemetry you can configure Consul for sending performance metrics to external tools/applications to monitor the performance of Consul. You can see some more information about configuring Consul for Telemetry on this page https://www.consul.io/docs/agent/options.html#telemetry. With this blogpost we will use the “statsd_address” option. In order to make this happen, we have to update our Consul configuration on the Consul Servers to add the following configuration:

    "telemetry": {
        "statsd_address": "192.168.1.202:9125"
    },

The IP Address is from the host itself, and in this case we have to send it to port 9125. Once we have configured this on all the Consul Servers, we need to restart them one by one so we keep the Consul Cluster running.

Configure statsd-exporter

When you use Prometheus, you’ll use exporters for your applications or databases to expose the metrics for Prometheus. Prometheus will scrape these metrics every 15 seconds (Well, you can configure that) and store them in the database. Consul doesn’t have an endpoint available to gather these metrics, we have to make use of the “statsd-exporter”. We already configured the Consul Servers to send metrics to a statsd server, so we only have to make sure we start one on each host running Consul Server.

Before we start an statsd-exporter, we first have to do some configuration first. We need to make sure we have a statd mapper file. With this file we map statsd fields into fields for prometheus and we can add labels per metric. On this page I have configured almost all mapping entries: https://gist.github.com/dj-wasabi/d9b31c4b74e561c72512f4edbdfe6927

Lets explain how an entry looks like:

consul.*.runtime.*
name="consul_runtime"
type="$2"
host="{{ inventory_hostname }}"

The first line in this mapping construction is the name of the statsd field. You’ll see asteriks, these are wildcards and these can be used as a value by assiging it to a filter. First asteric can be used as $1, second as $2 etc. The “name” is the name of the metric field in Prometheus, in this case the name is consul_runtime. Prometheus doesn’t accept dots in the names, so we have to use underscores for this.

We then create a label named “type” and we assign the value $2. The original statsd field that Consul has sent to the statsd-exporter looks like this:

consul.b139924a6f44.runtime.num_goroutines

With this mapping construction, we assign $1 with value b139924a6f44 and $2 with value num_goroutines. The last “host” label is something I add with Ansible. I use Ansible to deploy this statsd mapper file (And all other monitoring related configuration) to all my Consul servers and then I can filter in Prometheus or other graphing tool like Grafana which metrics belongs to which host.

I use the Docker container for the statsd-exporter, I place the statsd mapper file on /data/statsd-exporter.conf and start the following command:

docker run --name statsd-exporter \
-v /data/statsd-exporter.conf:/tmp/statsd-exporter.conf:ro \
-p 9102:9102 -p 9125:9125/udp prom/statsd-exporter \
-statsd.mapping-config=/tmp/statsd-exporter.conf \
-statsd.add-suffix=false

I mount the statsd mapper file as ro (Read Only), open 2 ports and configure the statsd-exporter tool to use the mapper file. In this case 2 ports are openend. One port on which the statsd is available for retrieving performance metrics (9125) and the other port (9102) is used for Prometheus to scrape these metrics.

Prometheus

At this moment, I have added the following into the Prometheus configuration to let Prometheus scrape the statsd-exporter metrics:

scrape_configs:
  - job_name: 'consul'
    static_configs:
      - targets: ['192.168.1.202:9102']
        labels:  {'host': 'vserver-202'}
      - targets: ['192.168.1.203:9102']
        labels:  {'host': 'vserver-203'}
      - targets: ['192.168.1.204:9102']
        labels:  {'host': 'vserver-204'}

This works for now because I Ansible to generate a Prometheus configuration, but I’ll go probably using a consul_sd_config in the near future so I won’t have to add all kinds of static configuration.

Once we have restarted Prometheus and started the statsd-exporter containers, I can see the following metrics appear in Prometheus:

consul_runtime{host="vserver-204",type="free_count"} 2.3117552e+08
consul_runtime{host="vserver-204",type="heap_objects"} 22853
consul_runtime{host="vserver-204",type="num_goroutines”} 82

(And much more, but the above 3 are examples which are used as an explanation in the previous paragraphs.)

Create some graphs

Now we have the metrics in Prometheus, but now we need to create some graphs. We use Grafana for this. Grafana can be used for creating Graphs to show the actual performance of Consul. I’ve created a Dashboard and uploaded it to grafana.com: https://grafana.com/dashboards/2351

Grafana Dashboard for Consul

Some of the following can be found on the dashboard:

  • Who is the Consul Leader;
  • How many Consul Servers are running?
  • Some CPU idle utilisation and load information (You’ll need the node-exporter for this);
  • Performance of writing information on the Consul leader to disk or the other nodes;
  • etc

This dashboard is not finished yet and is a mixed combination of Consul Leader data and Consul Server specific. So some graphs shows information specific to the selected Consul server (Dropdown at the top of the page) and some graphs show specific data for the Consul Leader.

If you have suggestions to improve the current situation, by either suggestion a better statsd mapper configuration file or for the Dashboard, please let me know so I can improve it. I hope we can all benefit from each other to improve the availability and performance of Consul with this.

Setting up a secure Vault with a Consul backend

vault_logo

With this blogpost we continue working with a secure Consul environment: We are configuring a secure Vault setup with Consul as backend. YMMV, but this is what I needed to configure to make it work.

Environment

We should have an working Consul Cluster environment. If you don’t have one, please take a look at here for creating one. With this blogpost we expect a secure Consul cluster with SSL certificates and using ACL’s.

In this blogpost we make use of the wdijkerman/vault container. This container is created by myself and is running Vault (At moment of writing release 0.6.4) on Alpine (running on 3.5). Vault is running as user ‘vault’ and the container can be configured to use SSL certificates.

prerequisites

We have to create SSL certificates for the vault service. In this blogpost we use the domain ‘dj-wasabi.local’, as Consul is already running with this domain configuration so we have to create ssl certificates for the FQDN: ‘vault.service.dj-wasabi.local’.

On my host where my OpenSSL CA configuration is stored, I execute the following commands:

openssl genrsa -out private/vault.service.dj-wasabi.local.key 4096

Generate the key.

openssl req -new -extensions usr_cert -sha256 -subj "/C=NL/ST=Utrecht/L=Nieuwegin/O=dj-wasabi/CN=vault.service.dj-wasabi.local" -key private/vault.service.dj-wasabi.local.key -out csr/vault.service.dj-wasabi.local.csr

Create a signing request file and then sign it with the CA.

openssl ca -batch -config /etc/pki/tls/openssl.cnf -notext -in csr/vault.service.dj-wasabi.local.csr -out certs/vault.service.dj-wasabi.local.crt

We copy the ‘vault.service.dj-wasabi.local.key’, ‘vault.service.dj-wasabi.local.crt’ and the caroot certificate file to the hosts which will be running the Vault container into the directory /data/vault/ssl. Hashicorp advises to run vault on hosts where Consul Agents are running, not Consul Servers. This has probably todo with that for most use cases they see is that Consul is part of large networks and thus the servers will handle a lot of request (High load). As the Consul Servers will be very busy, it would then be wise to not run anything else on those servers.

But this is my own versy small environment (With 10 machines) so I will run Vault on the hosts running the Consul Server.

ACL

Before we do anything on these hosts, we create a ACL in Consul. We have to make sure that Vault can create keys in the key/value store and we have to allow that Vault may create a service in Consul named vault.

So our (Client) ACL will look like this:

key "vault/" {
  policy = "write"
}
service "vault" {
  policy = "write"
}

We use this in the ui on the Consul Server and create the ACL. In my case, the ACL is created with id ’94c507b4-6be8-9132-ea15-3fc5b196ea29′. This ID is needed later on when we configure Vault. Also check your ACL for the ‘Anonymous token’. Please make sure you have set the following rule if the Consul default policy is set to deny:

service "vault" {
  policy = "read"
}

With this, we make sure the service is resolvable via dns. In my case this is for ‘vault.service.dj-wasabi.local’.

Configuration

We have to configure the vault docker container. We have to create a directory that will be mounted in the container. First we have to create an user on the host and then we create the directory: /data/vault/config and own it to the just created user.

useradd -u 994 vault
mkdir /data/vault/config
chown vault:vault /data/vault/config

The container is using a user named vault and has UID 994 and we have to make sure that everything is in sync with names and id. Now we create a config.hcl file in the earlier mentioned directory:

backend "consul" {
  address = "vserver-202.node.dc1.dj-wasabi.local:8500"
  check_timeout = "5s"
  path = "vault/"
  token = "94c507b4-6be8-9132-ea15-3fc5b196ea29"
  scheme = "https"
  tls_skip_verify = 0
  tls_key_file = "/vault/ssl/vault.service.dj-wasabi.local.key"
  tls_cert_file = "/vault/ssl/vault.service.dj-wasabi.local.crt”
  tls_ca_file = "/vault/ssl/dj-wasabi.local.pem"
}

listener "tcp" {
  address = "0.0.0.0:8200"
  tls_disable = 0
  tls_key_file = "/vault/ssl/vault.service.dj-wasabi.local.key"
  tls_cert_file = "/vault/ssl/vault.service.dj-wasabi.local.crt"
  cluster_address = "0.0.0.0:8201"
}

disable_mlock = false

First we configure a backend for Vault. As we use Consul, we use the Consul backend. Because the Consul is running on https and is using certificates, we have to use the fqdn of the Consul node as the address (same as how we did in configuring Registratror in this post). We also have to configure the options ‘tls_key_file’, ‘tls_cert_file’ and ‘tls_ca_file’, these are the ssl certificates needed for accessing the secure Consul via SSL. Because of this, we have to set the ‘scheme’ to ‘https’ and we have to specify the token for the ACL we created earlier and add the value to the the token option.

Next we configure the listener for Vault. We configure the listener that it listens on all ips on port 8200. We also make sure we configure the earlier created SSL certificates by using them in the ‘tls_key_file’ and ‘tls_cert_file’ options.

The last option is to make sure that Vault can not swap data to the local disk.

Starting Vault

Now we are ready to start the docker container. We use the following command for this:

docker run -d -h vserver-202 --name vault \
--dns=172.17.0.2 --dns-search=service.dj-wasabi.local \
--cap-add IPC_LOCK -p 8200:8200 -p 8201:8201 \
-v /data/vault/ssl:/vault/ssl:ro \
-e VAULT_ADDR=https://vault.service.dj-wasabi.local:8200 \
-e VAULT_CLUSTER_ADDR=https://192.168.1.202:8200 \
-e VAULT_REDIRECT_ADDR=https://192.168.1.202:8200 \
-e VAULT_ADVERTISE_ADDR=https://192.168.1.202:8200 \
-e VAULT_CACERT=/vault/ssl/dj-wasabi.local.pem \
wdijkerman/vault

We have the SSL certificates stored in the /data/vault/ssl and we mount these as read only on /vault/ssl. With the VAULT_ADDR we specifiy on which url the vault service is available on, this is the url which Consul provides like any other server. With the VAULT_CACERT we specify on which location the CA Certificate file of our domain. The other 3 environment variables are needed for a High Available Vault environment and is to make sure how other vault instances can contact it.

When Vault is started, we will see something like this with the docker logs vault command:

==> Vault server configuration:

Backend: consul (HA available)
Cgo: disabled
Cluster Address: https://192.168.1.202:8200
Listener 1: tcp (addr: "0.0.0.0:8200", cluster address: "0.0.0.0:8201", tls: "enabled")
Log Level: info
Mlock: supported: true, enabled: true
Redirect Address: https://192.168.1.202:8200
Version: Vault v0.6.4
Version Sha: f4adc7fa960ed8e828f94bc6785bcdbae8d1b263

==> Vault server started! Log data will stream in below:

But where are not done yet. When Vault is started, it is in a sealed state and because this is the first vault in the cluster we have to initialise it to. Also when you check the ui of Consul, you’ll see that the vault is in an error state. Why? When Vault starts, it automatically creates a service in Consul and add health checks. These health checks will check if a vault instance is sealed or not.

Initialise

As vault is running in the container, we open a terminal to the container:

docker exec -it vault bash

Now we have a bash shell running and we going to initialise vault. First we have to make sure we set the ‘VAULT_ADDR’ to this container, by executing the following command:

export VAULT_ADDR='https://127.0.0.1:8200'

Every time we want to do something with the vault instance, we have to set the ‘VAULT_ADDR’ to localhost. If we won’t do that, we will send the commands directly against the cluster.

As this is the first vault instance in the environment, we have to initialise it and we do that by executing the following command:

vault init -tls-skip-verify
Unseal Key 1: hemsIyJD+KQSWtKp0fQ0r109fOv8TUBnugGUKVl5zjAB
Unseal Key 2: lIiIaKI1F6pJ11Jw/g1CiLyZurpfhCM9AYIylrG/SKUC
Unseal Key 3: 298bn4H8bLbJRsPASOl3R+RPuDKIt6i5fYzqxQ3wL4ED
Unseal Key 4: W4RUiOU3IzQSZ8GD2z8jBEg2wK/q17ldr3zJipFjzKQE
Unseal Key 5: FNPHf8b+WCiS9lAzbdsWyxDgwic95DLZ03IR2S0sq4AF
Initial Root Token: ed220674-24da-d446-375d-bbd0334bcb31

Vault initialized with 5 keys and a key threshold of 3. Please
securely distribute the above keys. When the Vault is re-sealed,
restarted, or stopped, you must provide at least 3 of these keys
to unseal it again.

Vault does not store the master key. Without at least 3 keys,
your Vault will remain permanently sealed.

As we set the ‘VAULT_ADDR’ to ‘https://127.0.0.1:8200’, we have to add the ‘-tls-skip-verify’ option to the vault command. If we don’t do that, it will complain the it can not validate the certificate that matches the configured url ‘vault.service.dj-wasabi.local.

After executing the command, we see some output appear. This output is very important and needs to be saved somewhere on a secure location. The output provides us 5 unseal keys and the root token. Every time a vault instance is (re)started, the instance will be in a sealed state and needs to be unsealed. 3 of the 5 tokens needs to be used when you need to unseal a vault instance.

bash-4.3$ vault unseal -tls-skip-verify
Key (will be hidden):
Sealed: true
Key Shares: 5
Key Threshold: 3
Unseal Progress: 1
bash-4.3$ vault unseal -tls-skip-verify
Key (will be hidden):
Sealed: true
Key Shares: 5
Key Threshold: 3
Unseal Progress: 2
bash-4.3$ vault unseal -tls-skip-verify
Key (will be hidden):
Sealed: false
Key Shares: 5
Key Threshold: 3
Unseal Progress: 0

We have executed 3 times the unseal command and now this Vault instance is unsealed. You can see the ‘Unseal Progress’ changing after we enter an unseal key. We can verify that state of the vault instance by executing the vault status command:

bash-4.3$ vault status -tls-skip-verify
Sealed: false
Key Shares: 5
Key Threshold: 3
Unseal Progress: 0
Version: 0.6.4
Cluster Name: vault-cluster-7e01e371
Cluster ID: b9446acf-4551-e4c2-fa5f-03bd1bcf872f

High-Availability Enabled: true
Mode: active
Leader: https://192.168.1.202:8200

We see that this vault instance is not sealed and that the mode of this node is active. You can also see that the leader of the vault instance is in my case the current host. (Not strange as this is the first Vault instance of the environment.) If we want to add a 2nd and more, we have to execute the same commands as before. With the exception of the vault init command, as we already have an initialised environment.

As we are still logged in on the node, lets create a simple entry.

bash-4.3$ export VAULT_TOKEN=ed220674-24da-d446-375d-bbd0334bcb31
bash-4.3$ vault write secret/password value=secret
Success! Data written to: secret/password

We first set the ‘VAULT_TOKEN’ variable, this value of this variable is the value of the ‘Initial root token’. After that, we created a simple entry in the database. Key ‘secret/password’ is created and had the value ‘secret’.

It took some time to investigate how to setup a High Available Vault environment with Consul, not much information can be found on the internet. So maybe this page will help you setting one up yourself. If you do have improvements please let me know.

Configuring Access Control Lists in Consul

consul_logo

This is the 2nd post in securing Consul and this is about using ACLs in Consul. The first post (this one) we configured a Consul cluster by using gossip encryption and using SSL|TLS certificates. Now we cover the basics about Consul ACL’s (Access Control List) and configuring them in our cluster.

Master Token

First we have to create a master token. This is the token that has all rights (Thats why its called the master), sort of the ‘root’ token. We have to generate it first and we can use the uuidgen command in Linux (or Mac) for this. We use this output of the uuidgen command and place it in the following file: /data/consul/config/master-token.json

{
  "acl_master_token":"d9f1928e-1f84-407c-ab50-9579de563df5",
  "acl_datacenter":"dc1",
  "acl_default_policy":"deny",
  "acl_down_policy":"deny"
}

We have to store/configure this file on all Consul Servers. You’ll see that we set the default policy to “deny”, so we block everything and only enable the things we want. When we have created the file, we have to restart all Consul Servers to make the ACL’s active.

If you may recall what we did configure the Consul Server in the previous blogpost, we have configured the Consul Servers with this property:

"verify_incoming": true,

We have to open the ui on the Consul Server and because we have the property above configured, we need to load a SSL client certificate in our browser. (Or for now, you can also remove the property and restart Consul. But make sure you add it again when you are done!)

Now open the ui on the server and click on the right button (Settings). You’ll see something like this:

consul_settings

We enter the token we placed in the file in the field we see in our browser. Now we click on the button “ACL” (Token is saved automatically in your browser) and we see something like this:

consul_acl

This is an overview of all tokens available in Consul. You’ll see that 2 tokens exists in Consul right now:

  • Anonymous Token
  • Master Token

Anonymous Token

The anonymous token is used when you didn’t configure a Token in the settings page or didn’t supply it when using 3rd party software. You’ll only see the “consul” service, but won’t see anything else. If we would create a key in the key/value store, it will fail because the Anonymous token can’t do anything (Because of the property “acl_default_policy”:”deny”).

Master token

The master token is the token we just filled in the settings tab and the one configured in the json file in the beginning of this blogpost and is sort of the root token. The one token to rule them all.

So what do you need when you want to create an ACL? There are 3 types of policies that can be used:

  • read
  • write
  • deny

Might be obvious that the “read” policy is for reading data, “write” policy is for reading and writing data and “deny” is for NOT reading or writing data to Consul.

The ACL is written in the HCL language (HCL stands for HashiCorp Language) and we will create an ACL via the ui. You can also do that via the Consul API and automatically maintain them with for example Ansible, but that is out of the scope for this blogpost. In the ui we see on the right side of the page “New ACL”.

In the “name” field we enter for now “test” and select “client” as type. In the “Rules” field we enter the following:

key "" {
  policy = "read"
}
key "foo/" {
  policy = "write"
}

When we click on “create”, the ACL will be created. With this ACL, we choose the type “client” instead of the “management” type. When you have selected “management” as ACL type, the users/services which will use this ACL can also create/update/delete this and other ACL’s in the cluster. As we don’t want that, we select the “client” type.

We created 2 rules, both are for the key/value store. The first “key” rule specifies that all keys in the key/value store can be read with the ACL. With the 2nd “key” we specify that all keys in the “foo/” directory can be read and written. When we use this ACL, we can create the key “foo/bar”, but not the key “foobar”.

Next for using “key” in the rules, you can also configure “service”, “event” and “query” rules. It has the same format as the “key” example above and uses the same policies. With this you can easily give each application (or user) the correct rights.

Registrator

With registrator we can easily add docker containers as services into Consul. Now we have configured a default ACL policy to “deny” we have to update our configuration for the registrator. Registrator will attempt to sent the data to Consul for creating the services and registrator will think this is done, but Consul will deny because of the default policy. We can create a ACL specific to registrator.

Let’s create one via the UI. We enter the name “Registrator” and select “client” type. There are 2 possibilities to proceed regarding the “Rules”:

We can add a rule that will be used for all services the registry will add:

service "" {
  policy = "write"
}

Or we mention each service independently:

service "kibana" {
  policy = "write"
}
service "jenkins" {
  policy = "write"
}

Both have their pros and cons. With the first rule we allow that registrator can add all services into Consul and requires not much “maintenance”, it is a little bit to “open”. The 2nd rule requires more maintenance by adding all services but is more secure. With this, not all containers are added automatically and thus no rogue containers will be available in Consul.

We click on “create” to create the ACL. Now we have an token id and use that token in our docker run command. Our command to start registrator will look like this now:

docker run -h vserver-201 \
-v /var/run/docker.sock:/tmp/docker.sock \
-v /data/consul/config/ssl:/consul:ro \
-e CONSUL_CACERT=/consul/dj-wasabi.local.pem \
-e CONSUL_TLSCERT=/consul/vserver-201.node.dc1.dj-wasabi.local.crt \
-e CONSUL_TLSKEY=/consul/vserver-201.node.dc1.dj-wasabi.local.key \
-e CONSUL_HTTP_TOKEN=5c7d6559-cd90-d244-bbed-14d459a74bd2 \
gliderlabs/registrator:master \
-ip=192.168.1.201 consul-tls://vserver-201.node.dc1.dj-wasabi.local:8500

We had to add the -e CONSUL_HTTP_TOKEN variable with the token id as value. When I start the “kibana” container it will be added to Consul and we see the service is created.

We covered the basics for creating and using ACL’s in Consul. Using ACL’s in Consul will help securing Consul more by only allowing settings that is needed for the container purpose. Hopefully this will help you configuring ACLs in your environment.

Setting up a secure Consul cluster with docker

consul_logo

This post is the first of 2 blog items about setting up a secure Consul environment.

With the first post – which is this one – we will discuss how we setup a secure Consul environment. We will use a docker container and configure it with SSL certificates to secure the traffic from and to Consul. The 2nd post (This one), we will dive into ACLs and how we can make use of ACLs in Consul.

We will use the ‘wdijkerman/consul’ docker container to setup a secure environment. For now we create a Consul cluster with 2 hosts, named ‘vserver-201′ and ‘vserver-202′. ‘vserver-201′ will be the Consul Agent and ‘vserver-202′ will be the Consul Server. There is no specific need to use this container, you can also make this work with other Consul (containers) or installations.

Before we are going to setup the environment, we will briefly discuss the used docker container first.

wdijkerman/consul

This is a docker container created by myself which has Consul installed and configured. This container holds some basic Consul configuration and we can easily add some new configuration options by either supplying them to the command line or by creating a configuration json file. This container is running Consul 0.7.2 (Which is the latest version at moment of writing) and is running Alpine 3.5 (Also latest version at moment of writing). The most important thing is is that Consul isn’t running as user root, it is running as user ‘consul’ (with a fixed UID).

Before we start anything with the container, we going to add a user with that UID on the hosts running Consul.

useradd -u 995 consul

After this, we have to create 2 directories on the hosts running Consul. We use the following 2 directories:

mkdir -p /data/consul/data /data/consul/config
chown consul /data/consul/data /data/consul/config

The first directory is where Consul will store the Consul data and is only needed for the host running the Consul Server. The 2nd directory is where Consul will look for configuration files in which we create some files further in this post. On the host running the Consul Agent (In my case the host ‘vserver-201′) we only have to create the /data/consul/config directory. After the creation of the directories, we make sure these directories are owned by the earlier created user consul.

Before we are going to create some configuration files, take a look at the following json file. This json file is already present in the Consul docker container (So we don’t have to create it ourself) and is the default configuration of Consul:

{
  "data_dir": "/consul/data",
  "ui_dir": "/consul/ui",
  "log_level": "INFO",
  "client_addr": "0.0.0.0",
  "ports": {
    "dns": 53
  },
  "recursor": "8.8.8.8",
  "disable_update_check": true
}

As you see, this is a very basic configuration and we need to add some options to make it secure.

encrypt

We are going to expand our configuration by adding a new file in the /data/consul/config directory. With this file we are going to encrypt all of our internal Consul gossip traffic. This file should be placed on all of the hosts running Consul that will be/is part of this cluster.

Lets create a string with the following command:

docker run --rm --entrypoint consul wdijkerman/consul keygen

We use the output of this command and place it in the following file: /data/consul/config/encrypt.json

{
  "encrypt": "iuwMf/cScjTvKUKDC77kJA=="
}

We make sure that the rights of the file is set to 0400 and owned by the user consul.

chown consul:consul /data/consul/config/encrypt.json
chmod 0400 /data/consul/config/encrypt.json

All of the Consul nodes (Server and Agent) need this file, so make sure your Ansible (or Puppet, Chef or Saltstack) is configured to place this file on all of your nodes.

ssl

As all requests to and from Consul are done via http, we need to configure Consul that it listens on https instead of http. Before we do anything with Consul, we need access to a ssl crt, key and ca file first.

Before we execute a openssl command, we have to make sure that our CA SSL configuration is correct. Consul (Well, actually the go language: https://github.com/golang/go/issues/7423) requires some extra configuration specifically for using extentions in certificates. We have to add (or update) the property ‘extendedKeyUsage’ in the SSL CA configuration file so that the following values are added:

serverAuth,clientAuth

The usr_cert configuration in the CA openssl configuration file will look something like this:

[ usr_cert ]

basicConstraints=CA:FALSE
nsComment = "OpenSSL Generated Certificate"
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid,issuer
extendedKeyUsage = critical,timeStamping,serverAuth,clientAuth

(I have no idea why critical and timeStamping are there, so I just keep them there. :-))

We have to create the certificates now, the FQDN for this is:

<name_of_node>.node.<datacenter>.<domain>

In my case, my nodes are ‘vserver-201′ and ‘vserver-201′ , my domain is ‘dj-wasabi.local’ and have the default ‘dc1′ as datacenter. I need to create a crt and key for the host ‘vserver-201.node.dc1.dj-wasabi.local’ and ‘vserver-202.node.dc1.dj-wasabi.local’.

So on the host where my ‘dj-wasabi.local’ CA is configured, I need to execute the following set of commands:

cd /etc/pki/CA
openssl genrsa -out private/vserver-202.node.dc1.dj-wasabi.local.key 4096

We first generate the SSL key.

openssl req -new -extensions usr_cert -sha256 -subj "/C=NL/ST=Utrecht/L=Nieuwegin/O=dj-wasabi/CN=vserver-202.node.dc1.dj-wasabi.local" -key private/vserver-202.node.dc1.dj-wasabi.local.key -out csr/vserver-202.node.dc1.dj-wasabi.local.csr

We generate the csr file from the earlier created key.

openssl ca -batch -config /etc/pki/tls/openssl.cnf -notext -in csr/vserver-202.node.dc1.dj-wasabi.local.csr -out certs/vserver-202.node.dc1.dj-wasabi.local.crt

And now we will create a crt by signing the csr via the OpenSSL CA.

(And I do the same for host vserver-201.node.dc1.dj-wasabi.local)

Now we have to copy these files (Including the CA certificate file) to the servers and make sure these files are stored in the /data/consul/config directory, owned and only available by user consul. I create a ssl directory and places all the ssl files in this directory.

Now we have to create a configuration file, so Consul knows that it has SSL certificates. First we configure the Consul Server, in my case it is running on the ‘vserver-202′ host. We create the file /data/consul/config/ssl.json with the following content:

{
  "ca_file": "/consul/config/ssl/dj-wasabi.local.pem",
  "cert_file": "/consul/config/ssl/vserver-202.node.dc1.dj-wasabi.local.crt",
  "key_file": "/consul/config/ssl/vserver-202.node.dc1.dj-wasabi.local.key",
  "verify_incoming": true,
  "verify_outgoing": true
}

(Keep in mind that /data/consul/config is mounted in the container as /consul/config).

With the ‘verify_incoming‘ and ‘verify_outgoing‘ we make sure that all traffic to and from the Server is encrypted. If we would start the container right now, you can only access the ui if you have have created client ssl certificates and loaded it in your browser.

For the Consul agent, we use the same ssl.conf configuration file as mentioned above, but without the ‘verify_incoming‘ option.

ports

Before we start the container, we have to do 1 small thing. With a default configuration which we currently have, port 8500 is used for http. We create a new configuration file and assign the http listener to a different port number, so we can configure port 8500 to be https.

We create the file: /data/consul/config/ports.json with the following content:

{
  "ports": {
    "http": 8501,
    "https": 8500
  }
}

We have to specifiy the http port and give this a port number, otherwise it will be set default to 8500. When we start the container with the next step, we only configure port 8500 to be opened and not port 8501 and thus we have a https enabled Consul container.

Start Consul

Now we are able to start the Consul Server on the Consul server ‘vserver-202‘. We execute the following command:

docker run -h vserver-202 --name consul \
-v /data/consul/cluster:/consul/data \
-v /data/consul/config:/consul/config \
-p 8300:8300 -p 8301:8301 -p 8301:8301/udp \
-p 8302:8302 -p 8302:8302/udp -p 8400:8400 \
-p 8500:8500 -p 8600:53/udp wdijkerman/consul \
-server -ui -ui-dir /consul/ui -bootstrap-expect=1 \
-advertise 192.168.1.202 -domain dj-wasabi.local \
-recursor=8.8.8.8 -recursor=8.8.4.4

The following output appears:

[root@vserver-202 config]# docker logs consul
==> WARNING: BootstrapExpect Mode is specified as 1; this is the same as Bootstrap mode.
==> WARNING: Bootstrap mode enabled! Do not enable unless necessary
==> Starting Consul agent...
==> Starting Consul agent RPC...
==> Consul agent running!
Version: 'v0.7.2'
Node name: 'vserver-202'
Datacenter: 'dc1'
Server: true (bootstrap: false)
Client Addr: 0.0.0.0 (HTTP: 8501, HTTPS: 8500, DNS: 53, RPC: 8400)
Cluster Addr: 192.168.1.202 (LAN: 8301, WAN: 8302)
Gossip encrypt: true, RPC-TLS: true, TLS-Incoming: true
Atlas: <disabled>

==> Log data will now stream in as it occurs:

Most important in this output are these 2 lines:

Client Addr: 0.0.0.0 (HTTP: 8501, HTTPS: 8500, DNS: 53, RPC: 8400)
Gossip encrypt: true, RPC-TLS: true, TLS-Incoming: true

First line we can see that port 8500 is used for HTTPS and port 8501 is used for HTTP.
2nd line we see that the parameter encrypt is active (Is set to true) and both the ‘verify_incoming’ and ‘verify_outgoing’ are also set to true.

Now we can start Consul on the ‘vserver-201′ (Consul Agent):

docker run -h vserver-201 --name consul \
-v /data/consul/config:/consul/config \
-p 8300:8300 -p 8301:8301 -p 8301:8301/udp \
-p 8302:8302 -p 8302:8302/udp -p 8400:8400 \
-p 8500:8500 -p 8600:53/udp wdijkerman/consul \
-join 192.168.1.202 -advertise 192.168.1.201 \
-domain dj-wasabi.local

The Consul Agent will connect to the Consul Server and we can open the ui on the Agent with url https://vserver-201.dc1.dj-wasabi.local:8500. In my case it complains that the certificate is not validated (I’m using a self-signed CA certficate), but I’m able to access the ui and see the service ‘consul’. I do have an issue with opening the ui on the Consul Server. Why?

We have added the following property in the file /data/consul/config/ssl.json

"verify_incoming": true,

This means that ALL traffic to the Consul Server should be done via SSL certificates. If we really want to access the ui on the Consul Server (And we do want that, ACL’s ;-)) we have to create a client SSL certificate, load it in the browser and try opening the ui again.

Registrator

I use registrator in my environment and have to make sure that it can work with SSL to. For registrator, we have to configure 3 environment variables which are used for the locations of the ssl crt, key and ca file. To do this, we also have to mount the ssl directory in the registrator container so it has access to theses files.

Next, we have to use the consul-tls:// option instead of the consul:// when starting registrator.
Our command looks like this now:

docker run -h vserver-201 \
-v /var/run/docker.sock:/tmp/docker.sock \
-v /data/consul/config/ssl:/consul:ro \
-e CONSUL_CACERT=/consul/dj-wasabi.local.pem \
-e CONSUL_TLSCERT=/consul/vserver-201.node.dc1.dj-wasabi.local.crt \
-e CONSUL_TLSKEY=/consul/vserver-201.node.dc1.dj-wasabi.local.key \
gliderlabs/registrator:master \
-ip=192.168.1.201 consul-tls://vserver-201.node.dc1.dj-wasabi.local:8500

After executing the above command, new docker containers will be added automatically in Consul as a service via tls.

We successfully created a secure Consul environment where all traffic from and to Consul are encrypted. Even with the registrator tool we add new services via TLS connections.

Next blog item we will discuss the ACLs in Consul to make sure that not everyone can create/update/delete keys in the k/v store and or create/add/delete services.

Testing Ansible roles in a cluster setup with Docker and Molecule

ansible_logo_black_square

This page is updated on 2017-05-01.

This is a follow up on the previous 2 blog posts. With the first blog we discussed some steps to test your Ansible role with some basic steps. With the 2nd blog we added some features to extend our test by using CI tooling and group vars. With this post however, we might be configuring Molecule that will not occur very common with testing Ansible roles.

This time we configure Molecule for a role that is installing and configuring a cluster on Docker, like MySQL or MongoDB. We don’t go into a specific role (as there are so many), I only give some information on how to do this. We are only configuring Molecule for this setup, I’m still busy with running some specific TestInfra tests on a specific container.

Keep in mind these actions are only needed when using the {{ ansible_eth0.ipv4.address }} isn’t enough and you need a list with all ips.

For configuring Molecule, we’ll have to change 2 files:

  1. molecule.yml
  2. playbook.yml

molecule.yml

First we update the ‘molecule.yml’ file by configuring 3 (Or more, depends on what you need) docker containers. See the following example:

docker:
  containers:
  - name: node1
    ansible_groups:
      - cluster_service
    image: milcom/centos7-systemd
    image_version: latest
    privileged: True
    port_bindings:
      3306: 3306,
      4444: 4444
  - name: node2
    ansible_groups:
      - cluster_service
    image: milcom/centos7-systemd
    image_version: latest
    privileged: True
    port_bindings:
      3307: 3306,
      4445: 4444
  - name: node3
    ansible_groups:
      - cluster_service
    image: milcom/centos7-systemd
    image_version: latest
    privileged: True
    port_bindings:
      3308: 3306,
      4446: 4444

As you see, I have added the ‘port_bindings’ configuration to the instances, which is different with the examples in the previous blog posts. With the containers, we open the ports on the host (Before the ‘:’) and proxy them to the ports to the docker container (After the ‘:’ ).

In the above example, this ports configuration is used for configuring a MySQL (Or MariaDB) Galera cluster setup. You’ll have to update the ports configuration to your needs.

playbook.yml

Before we specify the roles in the ‘playbook.yml’, we add an ‘pre_tasks’. We add 2 blocks of code and will discuss them one by one. First we add the following in the ‘pre_tasks’ part:

    - name: "Get ip node 1"
      local_action: shell docker inspect --format \{\{.NetworkSettings.IPAddress\}\} node1
      register: node_ip_1
      changed_when: False
    - name: "Get ip node 2"
      local_action: shell docker inspect --format \{\{.NetworkSettings.IPAddress\}\}  node2
      register: node_ip_2
      changed_when: False
    - name: "Get ip node 3"
      local_action: shell docker inspect --format \{\{.NetworkSettings.IPAddress\}\}  node3
      register: node_ip_3
      changed_when: False

We have added 3 tasks, that do the same command but for each container. We execute a ‘docker inspect’ command to get the ip address of the docker container. As the docker inspect command used the ‘{{ .NetworkSettings.IPAddress }}’ format, Ansible will try to replace it because it thinks it is a variable. Luckily, we can make use of ‘{{ raw }} {{ endraw }}’ for this and Ansible will not use this as a variable anymore.

We register a variable, because we need to use the output, because the ‘docker inspect’ outputs the ip address. We also have to add the property ‘changed_when: False’.

What do you mean with the last one?

We have to fool Ansible with the ‘changed_when’ command for the ‘idempotence’ check. As this task will run every time, the ‘idempotence’ check will fail because of it (because it sees that there are tasks with state “Changed”).

Now we add the 2nd block of tasks to the ‘pre_tasks’, just after the first block of code we added earlier:

    - name: "Set fact"
      set_fact:
        node_ip: "{{ node_ip_1.stdout }}"
      when: inventory_hostname  == 'node1'
    - name: "Set fact"
      set_fact:
        node_ip: "{{ node_ip_2.stdout }}"
      when: inventory_hostname  == 'node2'
    - name: "Set fact"
      set_fact:
        node_ip: "{{ node_ip_3.stdout }}"
      when: inventory_hostname  == 'node3'

With this block we add 3 tasks again, 1 task for each container, to create a fact. In this case, I used to create the fact with the name ‘node_ip’, but you may name it differently. In my case when I use the ‘node_ip’ in my Ansible role, it get the actual IP of the host.

You can also create a list with all the ips if you need this in your role:

cluster_host_ips:
  - "{{ node_ip_1.stdout }}"
  - "{{ node_ip_2.stdout }}"
  - "{{ node_ip_3.stdout }}"

(You have to use the corrent name for the list of course 😉 )

I don’t know if this is the correct way, but it works in my case. I have a Jenkins job that validates a role that is configured to run a 3 node setup (Elasticsearch, MariaDB and some others).

If you have a other or a better way for doing this, please let me know!

Extending Ansible Role testing with Molecule by adding group_vars, dependencies and using travis ci

ansible_logo_black_square

This blog post will extend the actions we described on this https://werner-dijkerman.nl/2016/07/10/testing-ansible-roles-with-molecule-testinfra-and-docker/ page. We only configured a very basic configuration with 2 tests in the previously mentioned page, but thats not enough to and on this page we will continue to complete the tests. Github page for Molecule (In case you forgot 😉 )

We will discuss the following in this blogpost:

  • Make the TestInfra tests OS aware
  • Use group_vars
  • Role dependencies
  • Configure Travis

Lets dive into the tasks.

TestInfra OS Aware

Ok, not really molecule related, but very important if our role needs to work on several different operating systems. In the earlier mentioned blogpost we had configured Molecule to use a Ubuntu docker image. Before we can make the tests OS aware, we have to add some docker containers to the configuration which have different operating systems.

We create the following configuration:

docker:
  containers:
  - name: zabbix-agent-centos
    ansible_groups:
      - group1
    image: milcom/centos7-systemd
    image_version: latest
    privileged: True
  - name: zabbix-agent-debian
    ansible_groups:
      - group2
    image: maint/debian-systemd
    image_version: latest
    privileged: True
  - name: zabbix-agent-ubuntu
    ansible_groups:
      - group2
    image: rastasheep/ubuntu-sshd
    image_version: latest
    privileged: True

We have 3 docker containers configured: Ubuntu, Debian and CentOS. I’ve searched for Docker containers that have systemd configured, as the Zabbix Agent uses this. The official docker images of the mentioned OS’es doesn’t have the systemd enabled/configured.

We would like to run the ‘molecule test’ command, but it will fail on the ‘verify’ part.
We currently have this test:

def test_zabbix_package(Package, SystemInfo):
    zabbixagent = Package('zabbix-agent')
    assert zabbixagent.is_installed

    assert zabbixagent.version.startswith("3.0")

This test will validate if Zabbix is installed and the version starts with 3.0 (Thats the default version to be installed). When running this test, it will fail on the Debian and Ubuntu host. Why?They use a slightly different version naming than CentOS.

We have to update the function by adding the SystemInfo class to the function:

def test_zabbix_package(Package, SystemInfo):
    zabbixagent = Package('zabbix-agent')
    assert zabbixagent.is_installed

    if SystemInfo.distribution == 'debian':
        assert zabbixagent.version.startswith("1:3.0")
    if SystemInfo.distribution == 'centos':
        assert zabbixagent.version.startswith("3.0")

Now we have added the SystemInfo class to the function, we can use this to determine which tests we can execute on which OS. In the above example we see that if the distribution ‘debian’ is, we validate if the version starts with ‘1:3.0’. With CentOS we validate if it is ‘3.0’. When we execute the test on all 3 hosts, it will run successfully.

Using group_vars

This part also applies to using ‘host_vars’, just replace the word ‘group_vars’ with ‘host_vars’ 😉 We configure the molecule.yml file by adding some group_vars related data. We configure the 1st block in the molecule.yml like this:

ansible:
  playbook: playbook.yml
  group_vars:
    mysql:
      database_type: mysql
      database_type_long: mysql
    postgresql:
      database_type: pgsql
      database_type_long: postgresql
      postgresql_pg_hba_conf:
        - "host all all 127.0.0.1/32 trust"
        - "host all all ::1/128 trust"
      postgresql_pg_hba_local_ipv4: false
      postgresql_pg_hba_local_ipv6: false

This setup will “create” 2 group_var files: mysql and postgresql. When we run a molecule command, the group_vars will be created in the .molecule directory. Lets run a ‘molecule list’ command. For know we ignore the output, but lets see what is created in the .molecule directory:

[vagrant@localhost ansible-zabbix-server]$ find .molecule -type f | xargs ls -lrt
-rw-rw-r--. 1 501 games   3 Jul 17 20:31 .molecule/state
-rw-rw-r--. 1 501 games 215 Jul 17 20:31 .molecule/group_vars/postgresql
-rw-rw-r--. 1 501 games  51 Jul 17 20:31 .molecule/group_vars/mysql
[vagrant@localhost ansible-zabbix-server]$ cat .molecule/group_vars/mysql
---
database_type: mysql
database_type_long: mysql
[vagrant@localhost ansible-zabbix-server]$ cat .molecule/group_vars/postgresql
---
database_type: pgsql
database_type_long: postgresql
postgresql_pg_hba_conf:
- host all all 127.0.0.1/32 trust
- host all all ::1/128 trust
postgresql_pg_hba_local_ipv4: false
postgresql_pg_hba_local_ipv6: false

Within the .molecule directory a group_vars directory is created and 2 files are present (We will ignore the ‘state’ file). The output of these files are the same as how we configured the molecule.yml file.

Role dependencies

When your role has some dependencies, we really want them to download before we execute our role in Molecule. It will fail if we don’t do this. We have to download them first.

Molecule has a simple configuration for this. Within the molecule.yml file, we add the ‘requirements_file’ option in the Ansible configuration. Our example now looks like this:


dependency:
  name: galaxy
  requirements_file: requirements.yml 
  options:
    ignore-certs: True
    ignore-errors: True

ansible:
  playbook: playbook.yml
  group_vars:
    mysql:
      database_type: mysql
      database_type_long: mysql
    postgresql:
      database_type: pgsql
      database_type_long: postgresql
      postgresql_pg_hba_conf:
        - "host all all 127.0.0.1/32 trust"
        - "host all all ::1/128 trust"
      postgresql_pg_hba_local_ipv4: false
      postgresql_pg_hba_local_ipv6: false

In the root directory of the repository, a file called ‘requirements.yml’ is found which contains the dependencies.

When we run the ‘converge’ subcommand, the roles will be downloaded and after this the role is executed:

[vagrant@localhost ansible-zabbix-server]$ molecule converge
WARNING:vagrant:The Vagrant executable cannot be found. Please check if it is in the system path.
--> Installing role dependencies ...
- downloading role 'apache', owned by geerlingguy
- downloading role from https://github.com/geerlingguy/ansible-role-apache/archive/1.7.2.tar.gz
- extracting geerlingguy.apache to .molecule/roles/geerlingguy.apache
- geerlingguy.apache was installed successfully
- downloading role 'mysql', owned by geerlingguy
- downloading role from https://github.com/geerlingguy/ansible-role-mysql/archive/2.3.0.tar.gz
- extracting geerlingguy.mysql to .molecule/roles/geerlingguy.mysql
- geerlingguy.mysql was installed successfully
- downloading role 'postgresql', owned by galaxyprojectdotorg
- downloading role from https://github.com/galaxyproject/ansible-postgresql/archive/0.9.2.tar.gz
- extracting galaxyprojectdotorg.postgresql to .molecule/roles/galaxyprojectdotorg.postgresql
- galaxyprojectdotorg.postgresql was installed successfully
--> Starting Ansible Run ...

PLAY [all] *********************************************************************

TASK [setup] *******************************************************************
ok: [zabbix-server-centos-mysql]
... 
<snip>

Configure CI

We don’t want to run manually the molecule commands every time a change occurs. To quote Apple: “There is an app for that”. Well almost. I explain 2 ways of running Molecule in a automated way: Using Travis and Using Jenkins.

Travis

A commonly known cloud platform for CI, and it is very simple to make use of it. The Molecule documentation has a very nice example on how to configure the travis setup. We create in the root directory of our role, a file named: .travis.yml

sudo: required
language: python
services:
- docker

before_install:
- sudo apt-get -qq update
- sudo apt-get install -o Dpkg::Options::="--force-confold" --force-yes -y docker-engine

install:
- pip install molecule ansible docker

script:
- molecule test
notifications:
  webhooks: https://galaxy.ansible.com/api/v1/notifications/

Its a very basic travis configuration. First block is to let Travis know that we need to make use of sudo, that the language Python is and we use the ‘docker’ service.

2nd block is to update the Ubuntu’s apt cache and install Docker. When Docker is installed, we install molecule and after that, molecule test is executed. When the job is finished, we send some data via a web hook to the Ansible Galaxy page. The last step is to show the ‘passing’ (Or failing) badge on the Ansible Role page.

Jenkins

This example will show you a basic Jenkinsfile. I don’t do a single action manually in Jenkins. A  Jenkins job is basically code and we should use it as code. With Jenkins 2, we can make use of a Jenkinsfile (Also with Jenkins 1, but was named jenkins-template I believe?)

When you have a Jenkins server running, create a new Pipeline job and configure the correct git repository. (Okay, for this blogpost we do this manually, but I have a playbook for this. So this is on my part automated as well. 😉 )

A basic example:

node(){
    stage 'INFO: Checkout code'
        checkout scm
    stage 'Installing Molecule'
        sh 'sudo pip install molecule'
    stage 'Creating Containers'
        sh 'molecule create'
    stage 'Installing the Role'
        sh 'molecule converge'
    stage 'Idempotence check'
        sh 'molecule idempotence'
    stage 'Verify the application'
        sh 'molecule verify'
    stage 'Destroy the containers'
        sh 'molecule destroy'
}

When the job is executed, it will first download the Jenkinsfile from the configured git repository and the tasks will be executed one by one. This is just to get you started and the Jenkinsfile should be extended with some error handling like e-mail configuration etc.

So this was the follow up on the original blogpost for how to use Molecule with your Ansible role. The guys are really busy with Molecule so Molecule grows really fast. Maybe doing an 3rd blogpost very soon with new features.. 🙂

Testing Ansible roles with Molecule, Testinfra and Docker

ansible_logo_black_square

“On 2017-05-01 I’ve updated this post to the current situation. Some things where outdated and where removed.”

In some earlier posts I’ve described how you can use Test Kitchen for testing Ansible Roles (This one and the one extending it.). Test Kitchen was created for testing Chef Cookbooks and like Chef, Test Kitchen is a Ruby application. On this page we describe an other tool for the same purpose. This tool is what you might see as a Python clone of Test Kitchen, but more specific to Ansible: Molecule (Github)

Molecule isn’t that old, only few years and when I browse the internet it is not yet really known in the community. Unlike Test kitchen with the many different drivers, Molecule supports several backends, like Vagrant, Docker, and OpenStack. With Molecule you can make use of Serverspec (Like Test Kitchen), but you can also make use of ‘Testinfra’. Testinfra is like Serverspec a tool for writing unit tests, but it is written in Python.

Lets dive into Molecule and create some tests for Molecule. On this page, we make use of the Docker backend and if you following this page please install docker.

Installing Molecule is really simple:

pip install molecule docker

Voila, it is installed. With the installation of Molecule, Testinfra is installed to. We had to provide the docker module as well, otherwise molecule doesn’t know how to connect to the docker daemon. We can configure a Ansible Role. I used my ‘zabbix-agent’ role as test case for the Test Kitchen setup, so I will use it again for Molecule.

When you haven’t created an Ansible role yet, instead of using the ansible-galaxy command you can use the following command:

molecule init --driver docker --role role_name

This will create just like the ‘ansible-galaxy’ some default directories and files, but also gives us a starting point with a few extra files for testing this role with Molecule.

When you already have a working module and want to make use of Molecule, please execute the following command:

molecule init --driver docker

This will install several files specific for Molecule. No worries, we can recreate these files manually. Lets do that in a role and see what the files do.

File: <root>/molecule.yml

---
ansible:
  playbook: playbook.yml

driver:
  docker
docker:
  containers:
    - name: zabbix-01
      ansible_groups:
        - group1
      image: debian
      image_version: latest
      privileged: True

verifier:
  name: testinfra

This is the configuration file for Molecule. We specify which playbook Molecule will execute, in this case playbook.yml.
We specify that we want to make use of the Docker driver and that we have a docker container configuration. In this case, we only have 1 docker container specified. We use a Debian docker container with the ‘latest’ tag. We name the container ‘test-01’ and is in the group ‘group1’. And at last we configure molecule to use testinfra as the testtool.

File: <root>/playbook.yml

---
- hosts: all
  roles:
    - role: ansible-zabbix-agent

The playbook that is executed in the Docker container. This is a very basic one, we only have to specify the correct .

File: <root>/tests/inventory

localhost
[group1]
zabbix-01 ansible_connection=docker

The Ansible inventory file. Should be a known file to you 😉

File: <root>/tests/test_default.py


from testinfra.utils.ansible_runner import AnsibleRunner
testinfra_hosts = AnsibleRunner('.molecule/ansible_inventory').get_hosts('all')

def test_hosts_file(File):
    hosts = File('/etc/hosts')
    assert hosts.user == 'root'
    assert hosts.group == 'root' 

(Edit 2016-09-14: As of release 1.9, the first 2 lines should be present in the TestInfra script.)

This is the test infra python file, containing the tests. After the init command, we have 1 test that will check if there is a hosts file, and the user and group of the file belongs to user ‘root’. We discuss this file later on by adding some more tests.

File: <root>/tests/test.yml

---
- hosts: localhost
  remote_user: root
  roles:
    - zabbix-agent-role

Now we have discussed the files.

We add some infra test checks in the ‘test_default.py’ file. We add the following 2 tests:

def test_zabbix_package(Package):
    zabbixagent = Package('zabbix-agent')
    assert zabbixagent.is_installed
    assert zabbixagent.version.startswith("1:3.0")

def test_zabbixagent_running_and_enabled(Service):
    zabbixagent = Service("zabbix-agent")
    # assert zabbixagent.is_running
    assert zabbixagent.is_enabled

These are 2 Python function which are executed with Testinfra. With the first function, we validate if the package ‘zabbix-agent’ is installed. Also we check if the version starts with: 1:3.0. If you have some experience with testing Python code, this might be familiar to you. Test Infra uses ‘PyTest‘ to execute the tests and validate the.

The 2nd function we validate the ‘zabbix-agent’ service. We make sure the service is enabled. As you see, I’ve commented the check if the service is running. When it is enabled, I get this error message:

Failed to get D-Bus connection: Unknown error -1

Strange, because I’ve configured the privileged mode on the docker container. So maybe this is a bug or misconfiguration on my part, but for now I leave it commented and need to find a solution for this.

Within the molecule.yml we have to update the docker container configuration by adding the following property for all the docker containers:

    required: True

Now we added it, we have to do a “molecule destroy” and start again. The container will be recreated and we won’t get an error message about the dbus.

Now we are ready to move on (I’m well aware that these 2 tests that I added will not be enough, I’ll add these myself later on).

Molecule has several subcommands, let run molecule -h and see what is available:

No handlers could be found for logger "vagrant"
Usage:
    molecule [-hv] &amp;amp;lt;command&amp;amp;gt; [&amp;amp;lt;args&amp;amp;gt;...]

Commands:
    check         check playbook syntax
    create        create instances
    converge      create and provision instances
    idempotence   converge and check the output for changes
    test          run a full test cycle: destroy, create, converge, idempotency-check, verify and destroy instances
    verify        create, provision and test instances
    destroy       destroy instances
    status        show status of instances
    list          show available platforms, providers
    login         connects to instance via SSH
    init          creates the directory structure and files for a new Ansible role compatible with molecule

Options:
    -h --help     shows this screen
    -v --version  shows the version

We first start with the ‘check’ command:

[vagrant@localhost ansible-zabbix-agent]$ molecule check
No handlers could be found for logger "vagrant"

playbook: playbook.yml
[vagrant@localhost ansible-zabbix-agent]$ echo $?
0

Seems very well, the check commands validate if the playbook.yml doesn’t have any problems/syntax errors.
We can continue with the next command: create.

[vagrant@localhost ansible-zabbix-agent]$ molecule create
No handlers could be found for logger "vagrant"
 Building ansible compatible image ...
 Step 1 : FROM debian:latest

  ---&amp;amp;gt; 1b088884749b

 Step 2 : RUN bash -c 'if [ -x "$(command -v apt-get)" ]; then apt-get update &amp;amp;amp;&amp;amp;amp; apt-get install -y python sudo; fi'

  ---&amp;amp;gt; Using cache

  ---&amp;amp;gt; 8ef54383599a

 Step 3 : RUN bash -c 'if [ -x "$(command -v yum)" ]; then yum makecache fast &amp;amp;amp;&amp;amp;amp; yum update -y &amp;amp;amp;&amp;amp;amp; yum install -y python sudo; fi'

  ---&amp;amp;gt; Running in 6d3142fa72aa

...
 Finished building molecule_local/debian:latest
 Creating container zabbix-01 with base image debian:latest ...
 Container created.

[vagrant@localhost ansible-zabbix-agent]$

Now we have created a docker container where we can install our Ansible role on to, we do that with the ‘converge’ subcommand.

[vagrant@localhost ansible-zabbix-agent]$ molecule converge
No handlers could be found for logger "vagrant"

PLAY [all] *********************************************************************

TASK [setup] *******************************************************************
ok: [zabbix-01]

TASK [ansible-zabbix-agent : Include OS-specific variables] ********************
ok: [zabbix-01]

TASK [ansible-zabbix-agent : Install the correct repository] *******************
skipping: [zabbix-01]

...
RUNNING HANDLER [ansible-zabbix-agent : restart zabbix-agent] ******************
changed: [zabbix-01]

PLAY RECAP *********************************************************************
zabbix-01                  : ok=12  changed=7    unreachable=0    failed=0

Nice, the role is installed correctly without any issues on the container. With Test Kitchen we had to use BATS to validate if the Role is idempotent, but luckily molecule has just a simple sub command for it: idempotence

Well, it seems that the Role has passed the idempotence test:

[vagrant@localhost ansible-zabbix-agent]$ molecule idempotence
No handlers could be found for logger "vagrant"
Idempotence test in progress (can take a few minutes)...
Idempotence test passed.

[vagrant@localhost ansible-zabbix-agent]$

Testing the role is nicely going on right now, but we are not there yet. Now we need to use the ‘verify’ command to actually validate our role on the Docker container:

[vagrant@localhost ansible-zabbix-agent]$ molecule verify
No handlers could be found for logger "vagrant"
Trailing whitespace found in ./defaults/main.yml on lines: 35
Trailing newline found at the end of ./handlers/main.yml
Trailing whitespace found in ./library/zabbix_host.py on lines: 29
Trailing newline found at the end of ./library/zabbix_hostmacro.py
[vagrant@localhost ansible-zabbix-agent]$

Whoops, it seems it has found some issues. Let me fix that first, probably need to run the verify again after fixing it.

[vagrant@localhost ansible-zabbix-agent]$ molecule verify
No handlers could be found for logger "vagrant"

Executing testinfra tests found in tests/.
============================= test session starts ==============================
platform linux2 -- Python 2.7.5, pytest-2.9.2, py-1.4.31, pluggy-0.3.1
rootdir: /git/ansible/ansible-zabbix-agent/tests, inifile:
plugins: xdist-1.14, testinfra-1.4.0
collected 3 itemss

tests/test_default.py ...

=========================== 3 passed in 0.63 seconds ===========================

No serverspec tests found in spec/.

[vagrant@localhost ansible-zabbix-agent]$

After fixing it, everything seems to work fine. Nice!

Now we are done with the container, so we can execute molecule again, but with the delete sub command and the container will be deleted.

These were the basics for testing an Ansible role with Molecule, Docker and Test Infra. This page uses the ‘Debian’ Docker image, whereas I normally use CentOS for this. I have some issues (Get the same error message when I enable the Test Infra test to validate if the service is running) to make this work on CentOS. So maybe Molecule isn’t mature enough yet, but it is getting there.

I’ll update my Ansible roles so it will use Molecule instead of Test Kitchen (No hard feelings ;-))