Things to do before upgrading Kubernetes cluster - kubernetes

I have production stage hosted in Google Kubernetes Engine with Kubernetes version 1.12.9-gke.15.
My team is planning to upgrade it to Kubernetes version 1.13.11-gke.5.
A capture of list of Kubernetes version
I have read some articles to upgrade Kubernetes. However, they use kubeadm not GKE.
How to update api versions list in Kubernetes here's a example that use GKE.
If you guys have experience in upgrading kubernetes cluster in GKE or even kubeadm. Please share what should i do before upgrading the version ?
Should i upgrade the version to 1.13.7-gke.24 and then to 1.13.9-gke.3 and so on ?

You first should check if you are not using any depreciated features. For example check the Changelogs for version 1.12 and 1.13 to make sure you won't loose any functionality after the upgrade.
You will have to remember that if you have just one master node you will loose access to if for few minutes while control plane is being updated. After master node is set then worker nodes will follow.
There is a great post about Kubernetes best practices: upgrading your clusters with zero downtime, which talks about location for nodes and a beta option being Regional
When creating your cluster, be sure to select the “regional” option:
And that’s it! Kubernetes Engine automatically creates your nodes and masters in three zones, with the masters behind a load-balanced IP address, so the Kubernetes API will continue to work during an upgrade.
And they explain how does Rolling update works and how to do them.
Also you might consider familiarizing yourself with documentation for Cluster upgrades, as it discusses how automatic and manual upgrades work on GKE.
As you can see from your current version 1.12.9-gke.15 you cannot upgrade to 1.14.6-gke.1. You will need to upgrade to 1.13.11-gke.5 and once this is done you will be able to upgrade to latest GKE version.

GCP Kubernetes is upgraded manually and generally does not require you to do much. But if you are you looking for manual upgrade options maybe this will help.
https://cloud.google.com/kubernetes-engine/docs/how-to/upgrading-a-cluster
A point worth mentioning is too, make sure you have persistence volumes for services that require to do so viz. like DB, etc And for these, you will have to back them up manually.

Related

GKE automatically restarted cluster

Auto-Scaling is OFF and Cluster-Upgrade is OFF but still dont know why cluster get restarted today morning. All Nodes got replace/change and All Pods got restarted
Reason is that it got restarted due to node got upgrade from 1.22 to 1.23 version
I have Regular Version in GKE Cluster
You should double-check with Google support (if you have a support plan), but I know from painful experience that if you're running a version of GKE that falls out of support, they may force-upgrade you to keep you within support, even if you have cluster upgrade turned off -- unless you use a maintenance exclusion.
The REGULAR channel release notes are here: https://cloud.google.com/kubernetes-engine/docs/release-notes-regular
The December 5th one is probably the one that affected you.
If you disable node auto-upgrade, you are responsible for ensuring that the cluster's nodes run a version compatible with the cluster's version, and that the version adheres to the Kubernetes version and version skew support policy.
Nodes running versions that have reached their end of life date are auto-upgraded even when auto-upgrade is disabled, to ensure supportability and version skew compatibility.
For more information you can read this link.
You can also check this link for temporary mitigation.

Can new Rancher version be used for local cluster only?

I have been working with kubernetes in a staging environment for a couple of month and want to switch to production, I came across a tool called Rancher almost 2 weeks ago and since then am going through their documents.
It was recommended by the developers and also in the community not to use rancher in production kubernete and preferably create a separated cluster for that and add an agent to your main production cluster from that one.
However in the latest stable version, there is actually an option you can tick to use the rancher only for local cluster so this question came to my mind that:
If the latest stable version of rancher is modified to be deployed on production cluster itself rather than having dedicated cluster? and if there is any security or restarting issues can happen that deletes all the configurations for other components on cluster
Note: on another staging environment I installed on the local clustor an instance of wordpress and ghost and both were working fine.
I still think the best option for you would be to have fully accessible own cluster and you wont be dependent to rancher cloud solutions. I am not saying Rancher is bad - no. Just If you are talking about PRODUCTION environment - my personal opinion cluster should be own. Sure arguable topic.
What I can mention also here - you can use any of Useful Interactive Terminal and Graphical UI Tools for Kubernetes . for example Octant
Octant is a browser-based UI aimed at application developers giving
them visibility into how their application is running. I also think
this tool can really benefit anyone using K8s, especially if you
forget the various options to kubectl to inspect your K8s Cluster
and/or workloads. Octant is also a VMware Open Source project and it
is supported on Windows, Mac and Linux (including ARM) and runs
locally on a system that has access to a K8S Cluster. After installing
Octant, just type octant and it will start listening on localhost:7777
and you just launch your web browser to access the UI.

How to approach update of kops based kubernetes api's when upgrading the cluster?

Currently, we run kops based cluster of the version 15. We are planning to upgrade it to the version 16 first and then further. However, api versions for various kubernetes services in yaml's will also need to change. How would you address this issue before the cluster upgrade? Is there any way to enumerate all objects in the cluster with incompatible api versions or what would be the best approach for it? I suspect the objects created by kops, e.g. kube-system objects will be upgraded automatically.
When you upgrade the cluster, the API server will take care to upgrade all existing resources in the cluster. The problem arise when you want to deploy more resources and after the upgrade these are still using the old API versions. In this case your deployment (say kubectl apply) will fail.
I.e nothing already running in the cluster will break. But future deployments will if they still use old versions.
The resources managed by kOps already use new API versions.

Installing kubernetes on centos 7

I'm new in kubernetes and I have some doubts about the installation of kubernetes on centos 7, I have read some documentation on some links:
https://kubernetes.io/docs/getting-started-guides/kubeadm/
https://kubernetes.io/docs/getting-started-guides/centos/centos_manual_config/
But I not undestanding which procedure to follow, on first link it show how to install it using kubeadm but at the end of the article on "Limitations" appear that this tool "is a work in progress and these limitations will be addressed in due course", on second link I need to have at least 2 machines, so my question is which is better to use if I will to install it like production.
Thanks in advance
kubeadm.
kubeadm now can support for multi masters, which is considerable for production.
The kubeadm also supplies a secure deployment. It automatically configs TLS settings or RBAC for the cluster, which is not included in the "manual installation page".
My advice: play kubeadm in your development environment first, so that you see how kubeadm deploys a Kubernetes cluster, many components can be deployed by Kubernetes itself. Then, you decide whether use it in your production.
You can follow up the repository made by one of our developer with an additional thing of Horizontal Pod autoscaling of stateless application.
https://github.com/vevsatechnologies/Install-Kubernetes-on-CentOs

How to update Kubernetes Cluster to the latest version available?

I began to try Google Container Engine recently. I would you like to upgrade the Kubernetes Cluster to the latest version available, if possible without downtime. Is there any way to do this?
Unfortunately, the best answer we currently have is to create a new cluster and move your resources over, then delete the old one.
We are very actively working on making cluster upgrades reliable (both nodes and the master), but upgrades are unlikely to work for the majority of currently existing clusters.
We now have a checked-in upgrade tool for master and nodes: https://github.com/GoogleCloudPlatform/kubernetes/blob/master/cluster/gce/upgrade.sh