Tag Archives: openshift

RH OCP Header

OpenShift – Cluster-Monitoring-Operator Pod Error – cannot verify user is non-root

Kubernetes, , ,

The issue

After building a brand new OpenShift 4.6.9 cluster, I noticed one of the pods was not running correctly

oc get pods -n openshift-monitoring
.....
NAME READY   STATUS                       RESTARTS   AGE
cluster-monitoring-operator-f85f7bcb5-84jw5 1/2 CreateContainerConfigError 0 112m

Upon inspection of the pod;

oc describe pod cluster-monitoring-operator-XXX -n openshift-
monitoring

I could see the following error message;

Error: container has runAsNonRoot and image has non-numeric user
(nobody), cannot verify user is non-root

The Cause

There is a Red Hat article about this, but it is gated. The reason is cluster-monitoring-operator gets wrongly the non-root SCC assigned.

The Fix

Currently there is no permanent provided fix from Red Hat, but you can track this bug.

However the workaround is to simply delete the pod. This should recreate and load with the correct permissions.

Regards

Dean Lewis
OpenShift

How to specify your vSphere virtual machine resources when deploying Red Hat OpenShift

Kubernetes, VMware, ,

When deploying Red Hat OpenShift to VMware vSphere platform, there are two methods:

  • User Provisioned Infrastructure (UPI)
  • Installer Provisioned Infrastructure (IPI)

There are several great blogs covering both options and deployment methods.

In this blog, we are going to use the IPI method but customize the settings of our Virtual Machines that are deployed setting CPU and Memory that is different from the default settings.

Getting Started
Setting up your Jump host Machine

I’ll be using an Ubuntu Machine as my jumphost for the deployment.

Download the OpenShift-Install tool and OC command line tool. (I’ve used version 4.6.4 in my install)

Extract the files and copy to your /usr/bin/local directory

tar -zxvf openshift-client-linux.tar.gz
tar -zxvf openshift-install-linux.tar.gz

Have an available SSH key from your jump box, so that you can connect to your CoreOS VMs one they are deployed for troubleshooting purposes.

You need to download the vCenter trusted root certificates from your instance and import them to your Jump Host.

curl -O https://{vCenter_FQDN}/certs/download.zip

Then the following to import (ubuntu uses the .crt files, hence importing the win folder);

unzip download.zip
cp certs/win/* /usr/local/share/ca-certificates
update-ca-certificates

You will need an account to connect to vCenter with the correct permissions for the OpenShift-Install to deploy the cluster. If you do not want to use an existing account and permissions, you can use this PowerCLI script to create the roles with the correct privileges based on the Red Hat documentation.

If you are installing into VMware Cloud on AWS, like myself, you will also need to allow connectivity from your segments as follows:

  • Compute gateway
    • OCP Cluster network to the internet
    • OCP Cluster network to your SDDC Management Network
  • Management gateway
    • OCP Cluster network to ESXi – HTTPs traffic

DNS Records – You will need the two following records to be available on your OCP Cluster network in the same IP address space that your nodes will be deployed to.

  • {clusterID}.{domain_name}
    • example: ocp46.veducate.local
  • *.apps.{clusterID}.{domain_name}
    • example: *.apps.ocp46.veducate.local

If your DNS is a Windows server, you can use this script here. Continue reading How to specify your vSphere virtual machine resources when deploying Red Hat OpenShift →

OpenShift

Red Hat OpenShift on VMware vSphere – How to Scale and Edit your cluster deployments

Kubernetes, VMware, , , ,

Working with Red Hat OpenShift on vSphere, I’m really starting to understand the main infrastructure components and how everything fits together.

Next up was understanding how to control the cluster size after initial deployment. So, with Red Hat OpenShift, there are some basic concepts we need to understand first, before we jump into the technical how-to’s below in this blog.

In this blog I will cover the following;

- Understanding the concepts behind controlling Machines in OpenShift
- Editing your MachineSet to control your Virtual Machine Resources
- Editing your MachineSet to scale your cluster manually
- Deleting a node
- Configuring ClusterAutoscaler to automatically scale your environment

Machine API

The Machine API is a combination of primary resources that are based on the upstream Cluster API project and custom OpenShift Container Platform resources.

The Machine API performs all node host provisioning management actions as a post cluster installation method, providing you dynamic provisioning on top of your VMware vSphere platform (and other public/private cloud platforms).

The two primary resources are:

Machines
An object that describes the host for a Node. A machine has a providerSpec, which describes the types of compute nodes that are offered for different cloud platforms. For example, a machine type for a worker node on Amazon Web Services (AWS) might define a specific machine type and required metadata.
MachineSets
Groups of machines. MachineSets are to machines as ReplicaSets are to Pods. If you need more machines or must scale them down, you change the replicas field on the MachineSet to meet your compute need.

These custom resources add capabilities to your OpenShift cluster:

MachineAutoscaler
This resource automatically scales machines in a cloud. You can set the minimum and maximum scaling boundaries for nodes in a specified MachineSet, and the MachineAutoscaler maintains that range of nodes. The MachineAutoscaler object takes effect after a ClusterAutoscaler object exists. Both ClusterAutoscaler and MachineAutoscaler resources are made available by the ClusterAutoscalerOperator.
ClusterAutoscaler
This resource is based on the upstream ClusterAutoscaler project. In the OpenShift Container Platform implementation, this is integrated with the Machine API by extending the MachineSet API. You can set cluster-wide scaling limits for resources such as cores, nodes, memory, GPU, etc. You can configure priorities so that the cluster prioritizes pods so that new nodes are not brought online for less important pods. You can also set the ScalingPolicy, so that for example, you can scale up nodes but not scale down the node count.

MachineHealthCheck

This resource detects when a machine is unhealthy, deletes it, and, on supported platforms, creates a new machine. You can read more here about this technology preview feature in OCP 4.6.

Editing your MachineSet to control your Virtual Machine Resources

To view the current MachineSet objects available run; Continue reading Red Hat OpenShift on VMware vSphere – How to Scale and Edit your cluster deployments →

Kubernetes

How To Fix A PVC Stuck in Terminating Status in Kubernetes: Troubleshooting Guide

Kubernetes, , , , , , , , , ,

Having trouble deleting a persistent volume claim (PVC) stuck in “terminating“ status in Kubernetes/Openshift? We‘ve got the fix. Read on to learn how to patch the PVC to allow the final unmount and delete the PVC.

The Issue

Whilst working on a Kubernetes demo for a customer, I was cleaning up my environment and deleting persistent volume claims (PVC) that were no longer need.

I noticed that one PVC was stuck in “terminating” status for quite a while.

Kubernetes pvc terminating

Note: I am using the OC commands in place of kubectl due to this being a Openshift environment

The Cause

I had a quick google and found I needed to verify if the PVC is still attached to a node in the cluster.

kubectl get volumeattachment

I could see it was, and the reason behind this was the configuration for the PVC was not fully updated during the delete process.

Kubernetes pvc terminating kubectl get volumeattachment

The Fix

I found the fix on this github issue log .

You need to patch the PVC to set the “finalizers” setting to null, this allows the final unmount from the node, and the PVC can be deleted.

kubectl patch pvc {PVC_NAME} -p '{"metadata":{"finalizers":null}}'

Kubernetes pvc terminating kubectl patch pvc

Regards

Dean Lewis
OpenShift

Using the vSphere CSI Driver with OpenShift 4.x and VSAN File Services

Kubernetes, VMware, , , ,

You may have seen my blog post “How to Install and configure vSphere CSI Driver on OpenShift 4.x“.

Here I updated the vSphere CSI driver to work the additional security constraints that are baked into OpenShift 4.x.

Since then, once of the things that has been on my list to test is file volumes backed by vSAN File shares. This feature is available in vSphere 7.0.

Well I’m glad to report it does in fact work, by using my CSI driver (see above blog or my github), you can simply deploy consume VSAN File services, as per the documentation here. 

I’ve updated my examples in my github repository to get this working.

OK just tell me what to do…

First and foremost, you need to add additional configuration to the csi conf file (csi-vsphere-for-ocp.conf).

If you do not, the defaults will be assumed which is full read-write access from any IP to the file shares created.

[Global]

# run the following on your OCP cluster to get the ID 
# oc get clusterversion -o jsonpath='{.items[].spec.clusterID}{"\n"}'
cluster-id = c6d41ba1-3b67-4ae4-ab1e-3cd2e730e1f2

[NetPermissions "A"]
ips = "*"
permissions = "READ_WRITE"
rootsquash = false

[VirtualCenter "10.198.17.253"]
insecure-flag = "true"
user = "[email protected]"
password = "Admin!23"
port = "443"
datacenters = "vSAN-DC"
targetvSANFileShareDatastoreURLs = "ds:///vmfs/volumes/vsan:52c229eaf3afcda6-7c4116754aded2de/"

Next, create a storage class which is configured to consume VSAN File services.

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: file-services-sc
annotations:
storageclass.kubernetes.io/is-default-class: "false"
provisioner: csi.vsphere.vmware.com
parameters:
storagepolicyname: "vSAN Default Storage Policy" # Optional Parameter
csi.storage.k8s.io/fstype: "nfs4" # Optional Parameter

Then create a PVC to prove it works. Continue reading Using the vSphere CSI Driver with OpenShift 4.x and VSAN File Services →