Can I inherit node labels to pod labels?
i.e I want to have zone and instance-type labels from node to pods
This feature is not yet supported.
Here is an open feature request on kubernetes.
Though there are few workarounds.
You can also refers this, where they make use of initContainer to get node label and assign it to pod label.
Hope this helps.
Related
I'm using hardware-dependents pods; in my K8s, I instantiate my pods with a DaemonSet.
Now I want to access those pods with an URL like https://domain/{pod-hostname}/
My use case is a bit more tedious than this one. my pods' names are not predefined.
Moreover, I also need a REST entry point to list my pod's name or hostname.
I publish a Docker Image to solve my issue: urielch/dyn-ingress
My YAML configuration is in the Docker doc.
This Container add label on each pod, then use this label to create a service per pod, and then update an existing Ingress to reach each node with a path //
feel free to test it.
the source code is here
Problem:
I want every pod created in my cluster to hold\point the same data
e.g. let's say I want all of them to have an env vars like "OWNER=MYNAME".
there are multiple users in my cluster and I don't want them to start changing their YAMLs and manually assign OWNER:MYNAME to env.
Is there a way to have all current/future pods to be assigned automatically with a predefined value or mount a configmap so that the same information will be available in every single pod?
can this be done on the cluster level? namespace level?
I want it to be transparent to the user, meaning a user would apply whatever pod to the cluster, and the info could be available to him without even asking.
Thanks, everyone!
Pod Preset might help you here to partially achieve what you need. Pod Preset resource allows injecting additional runtime requirements into a Pod at creation time. You use label selectors to specify the Pods to which a given PodPreset applies.
Check this to know how pod preset works.
First you need to enable pod preset in your cluster.
You can use Pod Preset to inject env variables or volumes in your pod.
You can also inject configmap in your pod.
Make use of some common label for all the pods which you want to have common config, use this common label in your pod preset resource.
Unfortunately there are plans to remove pod presets altogether in coming releases, but I guess you can still use it with current releases. Although there are other implementations similar to pod presets, which you can try.
Is there any way to get a node labels from within a container for use as an environment variable?
It's similar to this https://kubernetes.io/docs/tasks/inject-data-application/environment-variable-expose-pod-information/, but I need to use a label from the node for injecting into the container instead.
Thanks in advance!
You will not be able to get node labels without sending some requests to the k8s api server. You could do that - but that would mean every pod will need read access and that's not great security wise.
How about an alternate solution - if you need to make sure the pod is running on nodes with specific labels, you can use taints and tolerations to achieve that more easily.
I am following up guide [1] to create multi-node K8S cluster which has 1 master and 2 nodes. Also, a label needs to set to each node respectively.
Node 1 - label name=orders
Node 2 - label name=payment
I know that above could be achieved running kubectl command
kubectl get nodes
kubectl label nodes <node-name> <label-key>=<label-value>
But I would like to know how to set label when creating a node. Node creation guidance is in [2].
Appreciate your input.
[1] https://coreos.com/kubernetes/docs/latest/getting-started.html
[2] https://coreos.com/kubernetes/docs/latest/deploy-workers.html
In fact there is a trivial way to achieve that since 1.3 or something like that.
What is responsible for registering your node is the kubelet process launched on it, all you need to do is pass it a flag like this --node-labels 'role=kubemaster'. This is how I differentiate nodes between different autoscaling groups in my AWS k8s cluster.
This answer is now incorrect (and has been for several versions of Kubernetes). Please see the correct answer by Radek 'Goblin' Pieczonka
There are a few options available to you. The easiest IMHO would be to use a systemd unit to install and configure kubectl, then run the kubectl label command. Alternatively, you could just use curl to update the labels in the node's metadata directly.
That being said, while I don't know your exact use case, the way you are using the labels on the nodes seems to be an effort to bypass some of Kubernetes key features, like dynamic scheduling of components across nodes. I would suggest rather than work on labeling the nodes automatically that you try to address why you need to identify the nodes in the first place.
I know this isn't creation time but, the following is pretty easy (labels follow pattern of key=value):
k label node minikube gpu.nvidia.com/model=Quadro_RTX_4000 node.coreweave.cloud/cpu=intel-xeon-v2
node/minikube labeled
I need to add the name of a kubernetes pod as a label to that pod when I create a pod using a replication controller. Is there a way to do that or should I do a patch once the pod is created?
There is no way to auto-promote the pod name into a label. You'll have to do that manually. Sorry.
Depending on what you're trying to do, a headless service may work for you:
http://kubernetes.io/v1.1/docs/user-guide/services.html#headless-services
Specify spec.clusterIP=None
DNS is ten configured to return multiple A records (addresses) for the Service name, which point directly to the Pods backing the Service.
Otherwise, you may want to follow progress on the PetSet proposal:
https://github.com/kubernetes/kubernetes/pull/18016