osimionica/dagota repository overview

⁠Dynomite on OpenShift as Statefulset

Dynomite (https://github.com/Netflix/dynomite⁠) is a distributed dynamo layer for redis and memcached hight availability. It is use to replicate each service with data and that's mainly what we need with OpenShift statefulsets.

Note: memcached is not tested at this time.

The project includes 2 docker images:

• dagota: https://hub.docker.com/r/smilelab/dagota/⁠ that is florida like server based on peer-finder (from kubernetes project). It search for pods in the statefulsets and setup a http server that can be used as florida provider in dynomite.
• dynomite: https://hub.docker.com/r/smilelab/dynomite/⁠ that is a simple dynomite image containing a startup script that creates configuration

Both images are based on openshift/base-centos7 image to be able to start without any user rights problem on OpenShift.

Also, this images should be coupled with a Redis container that listens on 22122 port (invert of memcached port 11211).

So that Pod has got 3 containers, one for dagota (to send detected peers to dynoite), dynomite that is used as redis proxy, and redis that is the service to use internally. You should make a service to bind on dynomite port (6379) and not on 22122, keep in mind that dynomite is the entrypoint.

You can try example at https://raw.githubusercontent.com/Smile-SA/dagota/master/dynomite.statefulset.test.yml⁠:

oc create -f https://raw.githubusercontent.com/Smile-SA/dagota/master/dynomite.statefulset.persistent.yml
# or, without storage
oc create -f https://raw.githubusercontent.com/Smile-SA/dagota/master/dynomite.statefulset.yml

Important You must use "dynomite:6379" (Service) from other pods to connect redis ! Don't connect to redis (22122).

Now you can try to SET/GET values:

$ oc run -it --name=redis-cli --image=redis --restart=Never -- bash
> redis-cli -h dynomite set foo "bar"
OK
> redis-cli -h dynomite get foo
"bar"
> exit

# then remove that pod
oc delete pod redis-cli --now

⁠Notes to not break your init

• Be sure that serviceName and SERVICE env var in statefulset are the same value as the Service name
• Be sure that clusterIP in service is set to None
• Check that redis is listening on 22122

⁠TODO

• Better dagota go code
• Test memcached
• Check why centos/redis-32-centos7 fails some connection while library/redis is ok
• livenessProbe and readinessProbe
• Volumes templates for redis