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How to install packages on alpine-based containers
2 min read
Whether you are running containers on Kubernetes or in docker you might need to install packages on the running containers. You will notice that most of them are based on Alpine Linux because of its small size.
Alpine Linux is a distribution based on musl and BusyBox with its own package-management system, apk-tools.
19/03/2021
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Using the nodeSelector for selecting a kubernetes cluster partition
4 min read
On a kubernetes cluster not all nodes are expected to have the same amount of resources so we might need to schedule some pods on specific nodes due to the resources they have (for example access to a GPU) or due to the network connectivity they have (for example edge nodes). Using nodeSelector we can the scheduler how we want out pods to be scheduled
18/03/2021
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Use kubie to simplify changes between kubernetes contexts and namespaces
2 min read
On another post we talked about how to change kubernetes context using kubectl and there's another post for setting a default namespace for a given context. kubie is a tool that helps trying to make it easier
17/03/2021
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kubernetes: List available API using kubectl
2 min read
With kubectl api-resources we can get the list of available objects, but the same object can be defined using different API versions, for example the Ingress object is different on v1beta1 compared to v1. Using kubectl api-versions we can get the list of all the available API versions on our kubernetes cluster
16/03/2021
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kubernetes: Get events across multiple objects
4 min read
The most commonly used way to get events is by using kubectl describe on each object like this:
$ kubectl describe pod pet2cattle-6597f8464d-hgxpp Name: pet2cattle-6597f8464d-hgxpp (...) Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Scheduled 3m47s default-scheduler Successfully assigned kube-system/pet2cattle-6597f8464d-hgxpp to scopuli.lolcathost.systemadmin.es Normal Pulled 3m46s kubelet Container image "172.18.1.46:5000/p2c:3.44" already present on machine Normal Created 3m46s kubelet Created container pet2cattle-sitemap Normal Started 3m46s kubelet Started container pet2cattle-sitemap Normal Pulled 3m41s kubelet Container image "172.18.1.46:5000/p2c:3.44" already present on machine Normal Created 3m41s kubelet Created container pet2cattle-indexer Normal Started 3m40s kubelet Started container pet2cattle-indexer Normal Pulled 3m32s kubelet Container image "172.18.1.46:5000/p2c:3.44" already present on machine Normal Created 3m32s kubelet Created container pet2cattle Normal Started 3m31s kubelet Started container pet2cattle Warning Unhealthy 3m26s kubelet Liveness probe failed: Get http://10.42.0.8:8000/: net/http: request canceled (Client.Timeout exceeded while awaiting headers)It's quite convenient when we are looking for events related to a given but becomes a pain if we need to see how the events are triggered on multiple objects.
15/03/2021
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