Kubernetes Operations (kops) Part 3: Updating Kubernetes Cluster

The video that follows is based on the material from The DevOps 2.3 Toolkit: Kubernetes.


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Kubernetes Resource Management Compared To Docker Swarm Equivalent

This article is part of the series that compare Kubernetes and Docker Swarm features.

Resource management can be divided into a few categories. We need to define how much memory and CPU we except a container will use and what are the limits. This information is crucial for a scheduler to make “intelligent” decisions when calculating where to place containers. In this aspect, there is no essential difference between Kubernetes and Docker Swarm. Both are using requested resources to decide where to deploy containers and limits when to evict them. Both of them are, more or less, the same in this aspect.
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Kubernetes RBAC Compared To Docker Swarm RBAC

This article is part of the series that compare Kubernetes and Docker Swarm features.

Docker has RBAC. Just as Kubernetes, it is organized around subjects, roles, and resource collections. In many aspects, both provide a very similar set of features. Should we quickly declare it a tie?

There is one crucial difference between Kubernetes RBAC and the one provided by Docker. The latter is not free. You’d need to purchase Docker Enterprise Edition (EE) to secure your cluster beyond “only those with the certificate can access it.” If you do have Docker EE, you already made up your mind, and the discussion whether to use one or the other is over. Docker EE is great, and soon it will work not only with Swarm but also with Kubernetes. You bought it, and there’s not much reason to switch to something else. However, this comparison focuses on what open source core versions can offer. It ignores third party and enterprise additions.
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Kubernetes Namespaces Compared To Docker Swarm Equivalent (If There Is Any)

This article is part of the series that compares Kubernetes and Docker Swarm features.

Docker Swarm does not have anything like Kubernetes Namespaces. We cannot split a Swarm cluster into sections. Therefore, we can finish this comparison by saying that Kubernetes is a clear winner regarding this feature since Docker Swarm doesn’t have Namespaces. But, that would not be entirely accurate.

Docker Swarm stacks are, in a way, similar to Kubernetes Namespaces. All the services in a stack are uniquely identified through a combination of a stack name and the names of services inside it. By default, all services within a stack can communicate with each other through the stack’s default network. Services can speak with those from other stacks only if they are explicitly attached to the same network. All in all, each Swarm stack is separated from other stacks. They are, in a way, similar to Kubernetes Namespaces.
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Kubernetes Secrets Compared To Docker Swarm Secrets

This article is part of the series that compares Kubernetes and Docker Swarm features.

Secrets are very similar to Kubernetes ConfigMaps and Docker Swarm configs. Everything we said for configurations applies to Secrets, with a few additional features.

Both Kubernetes and Docker Swarm stores Secrets in tmpfs inside containers. From that aspect, they are equally secure. The significant difference is in the way Secrets are stored internally.
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