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KUP - Automated Cluster Backup for Openshift

Make Openshift 4.x cluster backup easy as drink a Kup of a coffee

Table of Contents

Notes

This is the 2.0 version of Kup, now it no longer requires to add ssh-key to master nodes.
As I mainly re-wrote the script and the openshift manifests to make the script less "strictive" I highly recommend to switch at the new version where the pod use node-exporter capabilities to connect into the master nodes and run the backup script.
To update kup to the new version delete the running kup-backup project from the cluster and follow the "Upgrade" guides below The previous version of the images will be still available but tagged as xxx_old_notuse.

How it Works

Kup takes the backup of an Openshift cluster by archiving both ETCD and static pod backup.

The Kup backup process can be simplified in this step:

  1. The cronjob will schedule a pod on a master node

  2. Check the cluster health and "tag" the results in the backup

  3. Run the /usr/local/bin/cluster-backup.sh script

  4. Copy the archive output on a persistent volume specified on the cronjob

Repository Content

The Repository is formed by this elements:

  • manifest: directory with all the manifest template needed by the script

  • kup-values.conf: file with all the values to render in the template

  • kup-render.sh: script that will render the manifest with the kup-values to create the kup-install.yaml

Installation

Before starting to render the templates and install the final yaml, it's necessary to create a persistent volume and retrieve the cluster ssh key to access the nodes.

Add a persistent volume in the cluster

Kup need to use a persistent storage in order to store the Cluster backup in a consistent way.
Make sure to have the necessary space in the persistent volume to store all the backup you need. From my experience, one Kup backup archive takes from 15 MB to 19 MB of space.

If you need a manifest to create the persistent volume you can use the one below as starting point.

apiVersion: v1
kind: PersistentVolume
metadata:
  name: kup-backup-pv
spec:
  capacity:
    storage: 10Gi
  accessModes:
  - ReadWriteOnce
  nfs:
    path: /tmp
    server: 172.17.0.2
  persistentVolumeReclaimPolicy: Retain

More infos about provisioning persistent storage are present in the Persistent Storage pages of the Openshift docs with all the compatible type of volume in the "Configuring Persistent Volume" section

Set Kup values

Once both persistent volume and cluster ssh key are ready, it's possible to render the Kup manifests by first editing the kup-values.conf and then running the kup-render.sh script.

The kup-values.conf file has 2 type of values:

  • mandatory: have value setted to "change-me", must be changed for a correct one to work of Kup.

  • optional: have a default value that can be changed with something else to customize the default Kup behavior

Mandatory values are:

  • KUP_RENDER_PERSISTENT_VOLUME_NAME: name of the persistent volume created before

  • KUP_RENDER_OPENSHIFT_VERSION: version of the cluster, value can be in the format of 4.x or v4.x

If, for example, you have a cluster running with Openshift version 4.5.8, the correct version of Kup will be v4.5 or 4.5

To easily retrieve the Openshift version string to paste in the kup-values.conf run the oc version command or this snippet on the bastion host:

[mossicrue@bastion]$ oc version | grep "^Server Version:" | cut -d " " -f 3 | awk -F "." '{print "v"$1"."$2}'
v4.5

Render the manifests

After editing all the values in the kup-values.conf it's possible to render the manifest by running the kup-render.sh script.

The script, as for its usage, has 2 optional arguments:

  • -f FILE: path to Kup "values" file, default is kup-values.conf

  • -m PATH: path to the directory with the manifest to render, default is ./manifest

A simple command to run for render the manifest can be

[mossicrue@bastion]$ ./kup-render.sh -f kup-values.conf

After the script run, it will generate a new all-in-one manifest called kup-install.yaml

Apply the manifest

Once the kup-install.yaml file is generated you can copy it to your bastion server and create all the resources running

[mossicrue@bastion]$ oc apply -f kup-install.yaml

It will create the necessary objects in the kup-backup project/namespace.

Cluster status tag

If the kup-backup service account that run the cronjob has necessary priviliges, the job can also check the health of the cluster and tag the backup with the result of some checks.

Health Tag Meaning
sick-masters one or more master nodes are in "Not Ready" status
sick-workers one or more not-master nodes (worker, infra, ecc) are in "Not Ready" status
sick-cluster one or more master nodes and one or more not-master are in "Not Ready" status

Upgrading from Kup 1.0

If you have previously installed the old version of Kup follow these steps to upgrade Kup to the latest version:

  • Uninstall Kup from the cluster following the Uninstallation section
  • Fresh install Kup with the current version following the Installation section

Uninstallation

To uninstall Kup from your cluster follow this steps:

  • Release the persistent-volume claim from the kup-backup project
  • Delete the kup-backup project from the cluster
  • Delete the kup-backup-pv persistent volume from the cluster