Saturday, October 21, 2017

Cleaning Openshift Origin Images Registry

When using and tending an Openshift Origin cluster (for example, Origin version 3.7), it is normal to start the storage allocation in small sizes. However soon we find that storage for registry get filled up quickly with images from each build process. This post will show how to clean them up.

Preparation before pruning

First you need oc (origin client) binary and a user account with cluster administration capability.
If the openshift docker registry  is installed inside the cluster without external access, then you also going to need OS access to one of the hosts inside the cluster.
First step is to login to the cluster from your client or inside one of the hosts:
oc login

Prune steps

Reading the documentation (https://docs.openshift.com/enterprise/3.0/admin_guide/pruning_resources.html) we find that the pruning starts at deployment, then builds, and last images.

Pruning Deployment 

Run this to preview which deployment are going to be pruned:
oc adm prune deployments
Then execute the pruning :
oc adm prune deployments --confirm
We could use the CLI utility oadm (origin adm) or oc adm command, depending on availability of the executable.

Pruning Builds

Run this to preview the builds :
oc adm prune builds
or
oadm prune builds
Then execute the pruning :
oc adm prune builds --confirm

Pruning Registry Images

And finally, we prune images. Images could not be pruned if there are some deployments are referring to the image, thus the prune deployment  and build steps above are need to be done first.

oadm prune images
Confirm the pruning with additional --confirm flag:
oadm prune images --confirm

If we the registry is not accessible, we get this message :
error: error communicating with registry: Get http://IPredacted:5000/healthz: dial tcp IPredacted:5000: getsockopt: operation timed out
Such error means we need to ssh into one of the hosts in to be able to prune images.
 

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