rabbitmq-cluster-ocf-vagrant

Packer Build Scripts | Docker Image

A Vagrantfile to bootstrap and smoketest a RabbitMQ cluster by the pacemaker OCF RA. For details, see the docs.

With some luck, the script vagrant_script/conf_rabbit_primitive.sh may be updated to handle the latter one as well. Hopefully, we will merge them into the single OCF RA solution, eventually.

Vagrantfile

• Spins up two VM nodes [n1, n2] with predefined IP addressess 10.10.10.2-3/24 by default. Use the SLAVES_COUNT env var, if you need more nodes to form a cluster. Note, that the vagrant destroy shall accept the same number as well!
• Creates a corosync cluster with disabled quorum and STONITH.
• Launches a rabbitmq OCF multi-state pacemaker clone which should assemble the rabbit cluster automatically.
• Generates a command for a smoke test for the rabbit cluster. This may be run on one of the nodes (n1, n2, etc.). If the cluster assembles within couple of minutes, it puts RabbitMQ cluster smoke test: PASSED.
• Shares the host system docker daemon, images and containers. So you can launch nested containers as well.

Note, that constants from the Vagrantfile may be as well configred as vagrant-settings.yaml_defaults or vagrant-settings.yaml and will be overriden by environment variables, if specified.

Also note, that for workarounds implemented for the docker provider made the command vagrant ssh not working. Instead use the docker exec -it n1 bash or suchlike.

Known issues

• Vagrant docker provider networking is not implemented and there is no docker-exec privisioner to replace the ssh-based one. So I put ugly workarounds all around to make things working more or less.

• If vagrant destroy fails to teardown things, just repeat it few times more. Or use docker rm -f -v to force manual removal, but keep in mind that that will likely make your docker images directory eating more and more free space.

• Make sure there is no conflicting host networks exist, like packer-atlas-example0 or vagrant-libvirt or the like. Otherwise nodes may become isolated from the host system.

• The vagrant libvirt provider (plugin) may be broken for some cases. A w/a:

  vagrant plugin install --plugin-version 0.6.0 fog-libvirt
  

  or maybe via your RVM env and Ruby 2.6.0 to get the latest version:

  ~/.rvm/gems/ruby-2.6.0/wrappers/vagrant plugin install fog-libvirt
  

  (last time tested with Vagrant 2.2.16, make sure there is no vagrant-libvirt gem, nor the vagrant plugin installed!)

• If the terminal session looks "broken" after the vagrant up/down, issue a reset command as well.

Troubleshooting

You may want to use the command like:

VAGRANT_LOG=info SLAVES_COUNT=2 vagrant up --provider docker 2>&1| tee out

There was added "Crafted:", "Executing:" log entries for the provision shell scripts.

For the Rabbitmq OCF RA you may use the command like:

OCF_ROOT=/usr/lib/ocf /usr/lib/ocf/resource.d/rabbitmq/rabbitmq-server-ha monitor

It puts its logs under /var/log/syslog from the lrmd program tag.

Jepsen tests

NOTE: Works only with systemd based docker containers and the vagrant docker provider.

Jepsen is good to find out how resilient, consistent, available your distributed system is. For the Rabbitmq OCF RA case, there are custom tests to check if the cluster recovers from network partitions well. And history validation comes just as a free bonus :-) Although the jepsen test results may be ignored because it maybe rather related to the rabbitmq itself than to the OCF RA clusterer or a Pacemaker.

The idea is to bootstrap Pacemaker with Rabbitmq clusters and allow Jepsen to continuousely do hammering of the cluster with Nemesis strikes. Then check if the cluster has been recovered. And of cause you may want to look into the history validation results as well. Hopefully, that would give you insights on the rabbitmq server (or the pacemaker, or its rabbitmq resource) configuration settings!

Also note that both smoke and jepsen tests will perform an integration testing of the complete setup, which is Corosync/Pacemaker cluster plus the RabbitMQ cluster on top. Keep in mind that network partitions may kill the Pacemaker cluster as well making the rabbitmq OCF RA tests results irrelevant.

To proceed with jepsen tests, update ./conf files as required for a test case and define the env settings variables in the ./vagrant-settings.yaml_defaults file. For example, let's use jepsen_app: rabbitmq_ocf_pcmk, rabbit_ver: 3.5.7. And also let's adjust the rabbitmq partition recovery settings as

--- a/conf/rabbitmq.config
+++ b/conf/rabbitmq.config
@@ -10,7 +10,7 @@
          {exit_on_close, false}]
     },
     {loopback_users, []},
-    {cluster_partition_handling, autoheal},
+    {cluster_partition_handling, pause_minority},

Then set use_jepsen: "true" in the env settings and run vagrant up. It launches a control node n0 and five nodes named n1, n2, n3, n4, n5. Jepsen logs and results may be found in the shared volume named jepsen, in the /logs.

NOTE: The jepsen volume contains a shared state, like the lein docker image and the jepsen repo/jarfile/results, for consequent vagrant up/destroy runs. If something went wrong, you can safely delete it. Then it will be recreated from the scratch as well.

To collect logs at the host OS under the /tmp/results.tar.gz, use the command like:

docker run -it --rm -e "GZIP=-9" --entrypoint /bin/tar -v jepsen:/results:ro -v
/tmp:/out debian:latest cvzf /out/results.tar.gz /results/logs

To run lein commmands, use docker exec -it jepsen lein foo from the control node. For example, for the jepsen_app: jepsen, it may be:

docker exec -it jepsen lein test :only jepsen.core-test/ssh-test

And for the jepsen_app: rabbitmq_ocf_pcmk, it may be either:

docker exec -it jepsen lein test :only jepsen.rabbitmq_ocf_pcmk-test/rabbit-test

or just lein test, or even something like

bash -xx /vagrant/vagrant_script/lein_test.sh rabbitmq_ocf_pcmk

Travis CI job example

There is an example dummy job .travis.yml_example, which only deploys from the given branch of the rabbitmq-server OCF RA and does a smoke test. See also an upstream job config And here is a build example (on the clonned TravisCI upstream infra).