DaemonSets – Affinity – Taints – Tolerations
We are talking Kubernetes of course. Got to love the quirky IT naming conventions. Once you dig into the concepts behind the naming it all starts to make sense.
Today I learned about Node Affinity to control where your pods get deployed onto nodes as well DaemonSets, Taints and Tolerations.
Well, you can keep the “flys” away (stray pods) from your node by using taints and tolerations. Using taints you repel any pod deployment from landing on a node that does not have a toleration matching the taint. Basically the pod toleration inoculates the pod against the node taint, thus allowing it to be deployed into the node.
With node Selectors and Pod Affinity you direct pods to land only on their configured Selector matches with corresponding Node Selector names. That keeps the Pods from wandering onto Nodes where they should not be. While the Taints keep the “Flys” away and lets those Pods bounce to other non-tainted nodes. Pretty cool way to control Pod deployment onto properly resourced Nodes capable of handling the workload and resources demanded by the Pods.
DaemonSets are a way to ensure you always have a specific Pod on all of your nodes. Think logging Pods, Monitoring Pods, or any other service that needs to be in your nodes all of the time.
