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rfisher001 committed Feb 9, 2024
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140 changes: 140 additions & 0 deletions documentation/modules/ROOT/pages/OCP-upgrade-prep.adoc
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Expand Up @@ -90,3 +90,143 @@ image::LBorHT-MCP.jpg[]
image::Worker-MCP.jpg[]

The process and pace at which you un-pause the MCPs is determined by your CNFs and their configuration. Please review the sections on PDB and anti-affinity for CNFs. If your CNF can properly handle scheduling within an OpenShift cluster you can un-pause several MCPs at a time and set the MaxUnavailable to as high as 50%. This will allow as many as half of the nodes in an MCPs to restart and upgrade. This will reduce the amount of time that is needed for a specific maintenance window and allow your cluster to upgrade quickly.

=== Review your cluster for available MCPs and nodes

First you can run “oc get mcp” to show your current list of MCPs:

[source, bash]
----
# oc get mcp
NAME CONFIG UPDATED UPDATING DEGRADED MACHINECOUNT READYMACHINECOUNT UPDATEDMACHINECOUNT DEGRADEDMACHINECOUNT AGE
master rendered-master-b…e83 True False False 3 3 3
0 25d
worker rendered-worker-2….c4f True False False 2 2 2
0 25d
----

Now list out all of the nodes in your cluster:

NOTE: Review what is listed in the “ROLES” column, this will get updated as we move through this process.

[source, bash]
----
# oc get no
NAME STATUS ROLES AGE VERSION
euschannel-ctlplane-0.test.corp Ready master 25d v1.23.12+8a6bfe4
euschannel-ctlplane-1.test.corp Ready master 25d v1.23.12+8a6bfe4
euschannel-ctlplane-2.test.corp Ready master 25d v1.23.12+8a6bfe4
euschannel-worker-0.test.corp Ready worker 25d v1.23.12+8a6bfe4
euschannel-worker-1.test.corp Ready worker 25d v1.23.12+8a6bfe4
----

Determine, from the above suggestions, how you would like to separate out your worker nodes into machine config pools (MCP).

=== Create your MCPs

This is a 2 step process:

. We add a MCP label to each node
. We apply an MCP to the cluster which will organize the nodes based on their labels

NOTE: In the following example there are only 2 nodes and 2 MCPs. Therefore, each MCP only has 1 node in each.

==== Labeling nodes

We first need to label the nodes so that they can be put into MCPs. We will do this with the following commands:

[source, bash]
----
oc label node euschannel-worker-0.test.corp node-role.kubernetes.io/mcp-1=
oc label node euschannel-worker-1.test.corp node-role.kubernetes.io/mcp-2=
----

NOTE: The labels will show up when you run the “oc get node” command:

[source, bash]
----
# oc get no
NAME STATUS ROLES AGE VERSION
euschannel-ctlplane-0.test.corp Ready master 25d v1.23.12+8a6bfe4
euschannel-ctlplane-1.test.corp Ready master 25d v1.23.12+8a6bfe4
euschannel-ctlplane-2.test.corp Ready master 25d v1.23.12+8a6bfe4
euschannel-worker-0.test.corp Ready mcp-1,worker 25d v1.23.12+8a6bfe4
euschannel-worker-1.test.corp Ready mcp-2,worker 25d v1.23.12+8a6bfe4
----

==== Applying MCPs according to label

Now you need to create yaml files that will apply the labels as MCPs in your cluster. Each MCP will have to have a separate file or a separate section (as it is shown below).

Here is one example:

[source, bash]
----
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfigPool
metadata:
name: mcp-2
spec:
machineConfigSelector:
matchExpressions:
- {
key: machineconfiguration.openshift.io/role,
operator: In,
values: [worker,mcp-2]
}
nodeSelector:
matchLabels:
node-role.kubernetes.io/mcp-2: ""
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfigPool
metadata:
name: mcp-1
spec:
machineConfigSelector:
matchExpressions:
- {
key: machineconfiguration.openshift.io/role,
operator: In,
values: [worker,mcp-1]
}
nodeSelector:
matchLabels:
node-role.kubernetes.io/mcp-1: ""
----

Apply or create the MCPs through:

[source, bash]
----
# oc apply -f mcps.yaml
machineconfigpool.machineconfiguration.openshift.io/mcp-2 created
----

==== Monitor MCP formation
Now you can run “oc get mcp” again and your new MCPs will show. It will take a few minutes for your nodes to move into the new MCPs that they are assigned to. However, the nodes will NOT reboot during this time.

NOTE: You will still see the original worker and master MCPs that are part of the cluster.

This is what it will look like right after you apply the MCPs:
[source, bash]
----
# oc get mcp
NAME CONFIG UPDATED UPDATING DEGRADED MACHINECOUNT READYMACHINECOUNT UPDATEDMACHINECOUNT DEGRADEDMACHINECOUNT AGE
master rendered-master-b…e83 True False False 3 3 3 0 25d
mcp-1 rendered-mcp-1-2…c4f False True True 1 0 0 0 10s
mcp-2 rendered-mcp-2-2…c4f False True True 1 0 0 0 10s
worker rendered-worker-2…c4f False True True 0 0 0 2 25d
----

This is what it will look like after the MCPs have been completely applied:
[source, bash]
----
# oc get mcp
NAME CONFIG UPDATED UPDATING DEGRADED MACHINECOUNT READYMACHINECOUNT UPDATEDMACHINECOUNT DEGRADEDMACHINECOUNT AGE
master rendered-master-b…e83 True False False 3 3 3 0 25d
mcp-1 rendered-mcp-1-2…c4f True False False 1 1 1 0 7m33s
mcp-2 rendered-mcp-2-2…c4f True False False 1 1 1 0 51s
worker rendered-worker-2…c4f True False False 0 0 0 0 25d
----
4 changes: 2 additions & 2 deletions site.yml
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Expand Up @@ -15,7 +15,7 @@ content:

asciidoc:
attributes:
release-version: 4.12To4.14
release-version: 4.12-4.14
page-pagination: true
extensions:
- ./lib/tab-block.js
Expand All @@ -32,4 +32,4 @@ ui:
contents: "static_files: [ .nojekyll ]"

output:
dir: ./gh-pages
dir: ./gh-pages

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