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
Related
Well, my question is really short and hopefully simple? Is it possible to add a cacerts file automatically in every pod in a specific Kubernetes cluster?
According to this article it's possible by creating a ConfigMap and add this to the path /etc/ssl/certs/. But is it possible to achieve this on a higher level so that all pods in a Kubernetes cluster have this cacerts file?
You can add a MutatingAdmissionWebhook for a pod, which adds the folder by default as a volume to each pod. Check out the docs about MutatingAdmissionWebhooks and writing an admission webhook.
This way you add a "service", which mutates the pod config before the scheduler handles it. Check out this for a quick example.
Summarize the problem:
Any way we can add an ENV to a pod or a new pod in kubernetes?
For example, I want to add HTTP_PROXY to many pods and the new pods it will generate in kubeflow 1.4. So these pods can be access to internet.
Describe what you’ve tried:
I searched and found istio maybe do that, but it's too complex for me.
The second, there are too many yamls in kubeflow, as to I cannot modify them one by one to use configmap or add ENV just in them.
So anyone has a good simle way to do this? Like doing this in kubernetes configuation.
Use "PodPreset" object to inject common environment variables and other params to all the matching pods.
Please follow below article
https://v1-19.docs.kubernetes.io/docs/tasks/inject-data-application/podpreset/
If PodPreset is indeed removed from v1.20, then you seem to need a webhook.
You will have to run an additional service in your cluster that will change the configuration of the pods.
Here is an example, on the basis of which I created my webhook, which changed the configuration of the pods in the cluster, in this example the developer used the logic adding a sidecar to the pod, but you can set your own to forward the required ENV:
https://github.com/morvencao/kube-mutating-webhook-tutorial/blob/master/medium-article.md
I have used some bitnami charts in my kubernetes app. In my pod, there is a file whose path is /etc/settings/test.html. I want to override the file. When I search it, I figured out that I should mount my file by creating a configmap. But how can I use the created configmap with the existed pod . Many of the examples creates a new pod and uses the created config map. But I dont want to create a new pod, I wnat to use the existed pod.
Thanks
If not all then almost all pod specs are immutable, meaning that you can't change them without destroying the old pod and creating a new one with desired parameters. There is no way to edit pod volume list without recreating it.
The reason behind this is that pods aren't meant to be immortal. Pods meant to be temporary units that can be spawned/destroyed according to scheduler needs. In general, you need a workload object that does pod management for you (a Deployement, StatefulSet, Job, or DaemonSet, depenging on deployment strategy and application nature).
There are two ways to edit a file in an existing pod: either by using kubectl exec and console commands to edit the file in place, or kubectl cp to copy an already edited file into the pod. I advise you against both of these, because this is not permanent. Better backup the necessary data, switch deployment type to Deployment with one replica, then go with mounting a configMap as you read on the Internet.
I was trying to make file before application gets up in kubernetes cluster with initcontainers,
But when i am setting up the pod.yaml and trying to apply it with "kubectl apply -f pod.yaml" it throws below error
error-image
Like the error says, you cannot update a Pod adding or removing containers. To quote the documentation ( https://kubernetes.io/docs/concepts/workloads/pods/#pod-update-and-replacement )
Kubernetes doesn't prevent you from managing Pods directly. It is
possible to update some fields of a running Pod, in place. However,
Pod update operations like patch, and replace have some limitations
This is because usually, you don't create Pods directly, instead you use Deployments, Jobs, StatefulSets (and more) which are high-level resources that defines Pods templates. When you modify the template, Kubernetes simply delete the old Pod and then schedule the new version.
In your case:
you could delete the pod first, then create it again with the new specs you defined. But take into consideration that the Pod may be scheduled on a different node of the cluster (if you have more than one) and that may have a different IP Address as Pods are disposable entities.
Change your definition with a slightly more complex one, a Deployment ( https://kubernetes.io/docs/concepts/workloads/controllers/deployment/ ) which can be changed as desired and, each time you'll make a change to its definition, the old Pod will be removed and a new one will be scheduled.
From the spec of your Pod, I see that you are using a volume to share data between the init container and the main container. This is the optimal way but you don't necessarily need to use a hostPath. If the only needs for the volume is to share data between init container and other containers, you can simply use emptyDir type, which acts as a temporary volume that can be shared between containers and that will be cleaned up when the Pod is removed from the cluster for any reason.
You can check the documentation here: https://kubernetes.io/docs/concepts/storage/volumes/#emptydir
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