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Alen Komljen

Total 17 Posts

I help companies to embrace DevOps and Cloud Native.

  • Sarajevo
kubernetes | ceph | persistent storage

Using Existing Ceph Cluster for Kubernetes Persistent Storage

I wrote about Rook storage a few weeks ago, but maybe you already have Ceph cluster running in your datacenter. Or you prefer to use Ceph on separate nodes and without Kubernetes. Also, currently Rook is alpha software and not ready for production use. I would assume that this large Ceph cluster if you have one, is also used for other services outside Kubernetes. Whatever is the case it is simple to connect Ceph and Kubernetes together to provision persistent ...

kubernetes | persistent storage | resize

Easy Way to Resize Kuberntes Persistent Volumes

The previous post about Rook got great attention from the community. But, I also got a lot of questions about persistence on Kubernetes in general. Among many questions, there were a few about resizing persistent volume claims or PVCs. If you are using on-premises storage solutions like Ceph (Rook) this is not the big issue. The part of the reason is that when you create a volume in Ceph, let's say a 100GB, this space is not actually allocated. But, ...

kubernetes | rook | ceph | persistent storage

Rook: Cloud Native On-Premises Persistent Storage for Kubernetes on Kubernetes

Software defined storage is not something new. One of the most popular is Ceph. I started with Ceph five years ago because I was looking into unified storage for OpenStack. There are many other solutions, but I like the Ceph because it is all in one solution for the block, object and file storage, and it is opensource. Inktank the company behind Ceph is later acquired by RedHat, but that made things even better. If you already have Ceph cluster ...

kubernetes | jenkins | ci/cd | pipeline

Set Up a Jenkins CI/CD Pipeline with Kubernetes

Continuous integration and delivery or CI/CD is the most important part of DevOps, and cloud native too. CI/CD connects all the bits together. With access to Kubernetes cluster deploying Jenkins server is easy. Of course thanks to Helm. But, deploying Jenkins server is the easy part. The hard part is creating pipeline which will build, deploy and test your software. The focus of this post is understanding the Jenkins pipeline and what is happening in the background when ...

applications | kubernetes | troubleshooting

Troubleshoot Applications Running on Kubernetes

I'm writing a lot of about Kubernetes for a few months already. The reason for that is that I like the idea of cloud-native apps. There is a huge amount of easily installable apps for Kubernetes out there. One of the biggest resources of "Kube ready" apps is Kubeapps Hub. A week ago, when I submitted the Sematext Docker Agent to the stable charts repo there were 149 apps. At the time of writing, there is already 157 ...

kubernetes | service mesh

Kubernetes Service Mesh

A few months ago my colleague asked me what I think about integrating Linkerd to our new application running on Kubernetes. My first thought was, heck, isn't Kubernetes service and ingress enough? You can do a lot of stuff with it. Having a service mesh seemed like an overhead to me. You often have some API which is available only on the internal network. But, this is not the case anymore with modern apps. The API is probably exposed to ...