I've used the Bitnami Helm chart to install SCDF into a k8s cluster generated by kOps in AWS.
I'm trying to add my development SCDF stream apps into the installation using a file URI and cannot figure-out where or how the shared Skipper & Server mount point is. exec'ing into either instance there is no /home/cnb and I'm not seeing anything common via mount. The best I can tell the Bitnami installation is using the MariaDB instance for shared "storage".
Is there a recommended way of installing local/dev Stream apps into the cluster?
There are a couple of parameters under the deployer section that allows you to mount volumes (link):
deployer:
## #param deployer.volumeMounts Streaming applications extra volume mounts
##
volumeMounts: {}
## #param deployer.volumes Streaming applications extra volumes
##
volumes: {}
see https://github.com/bitnami/charts/tree/master/bitnami/spring-cloud-dataflow#deployer-parameters.
Then, the mounted volume is used in the ConfigMaps (both server and skipper):
Server
https://github.com/bitnami/charts/blob/c351211a5501bb44b5e065a5e3a7d4b7414f84f3/bitnami/spring-cloud-dataflow/templates/server/configmap.yaml#L60
Skipper
https://github.com/bitnami/charts/blob/c351211a5501bb44b5e065a5e3a7d4b7414f84f3/bitnami/spring-cloud-dataflow/templates/skipper/configmap.yaml#L72
Apart from that, there are also server.extraVolumes and server.extraVolumeMounts to be set on the Dataflow Server Pod, and skipper.extraVolumes and skipper.extraVolumeMounts to be set on the Skipper Pod just in case it's useful for your use case.
Building on the previous answer here is what I came-up with:
Create an EBS Volume
Mount it on each EC2 instance in the cluster at the same location (/cdf)
Install CDF using the Bitnami chart and this config file:
server.extraVolumeMounts:
# Locstion in container
- mountPath: /applications
# Refer to the volume below
name: application-volume
server.extraVolumes:
- name: application-volume
hostPath:
# Location in host filesystem
path: /cdf
# this field is optional
type: Directory
skipper.extraVolumeMounts:
# Locstion in container
- mountPath: /applications
# Refer to the volume below
name: application-volume
skipper.extraVolumes:
- name: application-volume
hostPath:
# Location in host filesystem
path: /cdf
# this field is optional
type: Directory
Then I can copy my jars into /cdf on the host file system and install the applications using a file URI of file:///applications/<jar-file-name> and everything works.
Related
I am trying to configure SSL for the Kubernetes Dashboard. Unfortunately I receive the following error:
2020/07/16 11:25:44 Creating in-cluster Sidecar client
2020/07/16 11:25:44 Error while loading dashboard server certificates. Reason: open /certs/tls.crt: no such file or directory
volumeMounts:
- name: certificates
mountPath: /certs
# Create on-disk volume to store exec logs
I think that /certs should be mounted, but where should it be mounted?
Certificates are stored as secrets. Then secret can be used and mounted in a deployment.
So in your example it would look something like this:
...
volumeMounts:
- name: certificates
mountPath: /certs
# Create on-disk volume to store exec logs
...
volumes:
- name: certificates
secret:
secretName: certificates
...
This is just a short snipped of the whole process of setting up Kubernetes Dashboard v2.0.0 with recommended.yaml.
If you did used the recommended.yaml then certs are created automatically and stored in memory. Deployment is being created with args : -auto-generate-certificates
I also recommend reading How to expose your Kubernetes Dashboard with cert-manager as it might be helpful to you.
There already was an issue submitted with a simmilar problem as yours Couldn't read CA certificate: open : no such file or directory #2518 but it's regarding Kubernetes v1.7.5
If you have any more issues let me know I'll update the answer if you provide more details.
What do I have to put into a container to get the agent to run? Just libjprofilerti.so on its own doesn't work, I get
Could not find agent.jar. The agentpath parameter must point to
libjprofilerti.so in an unmodified JProfiler installation.
which sounds like obvious nonsense to me - surely I can't have to install over 137.5 MB of files, 99% of which will be irrelevant, in each container in which I want to profile something?
-agentpath:/path/to/libjprofilerti.so=nowait
An approach is to use Init Container.
The idea is to have an image for JProfiler separate from the application's image. Use the JProfiler image for an Init Container; the Init Container copies the JProfiler installation to a volume shared between that Init Container and the other Containers that will be started in the Pod. This way, the JVM can reference at startup time the JProfiler agent from the shared volume.
It goes something like this (more details are in this blog article):
Define a new volume:
volumes:
- name: jprofiler
emptyDir: {}
Add an Init Container:
initContainers:
- name: jprofiler-init
image: <JPROFILER_IMAGE:TAG>
command: ["/bin/sh", "-c", "cp -R /jprofiler/ /tmp/"]
volumeMounts:
- name: jprofiler
mountPath: "/tmp/jprofiler"
Replace /jprofiler/ above with the correct path to the installation directory in the JProfiler's image. Notice that the copy command will create /tmp/jprofiler directory under which the JProfiler installation will go - that is used as mount path.
Define volume mount:
volumeMounts:
- name: jprofiler
mountPath: /jprofiler
Add to the JVM startup arguments JProfiler as an agent:
-agentpath:/jprofiler/bin/linux-x64/libjprofilerti.so=port=8849
Notice that there isn't a "nowait" argument. That will cause the JVM to block at startup and wait for a JProfiler GUI to connect. The reason is that with this configuration the profiling agent will receive its profiling settings from the JProfiler GUI.
Change the application deployment to start with only one replica. Alternatively, start with zero replicas and scale to one when ready to start profiling.
To connect from the JProfiler's GUI to the remote JVM:
Find out the name of the pod (e.g. kubectl -n <namespace> get pods) and set up port forwarding to it:
kubectl -n <namespace> <pod-name> port-forward 8849:8849
Start JProfiler up locally and point it to 127.0.0.1, port 8849.
Change the local port 8849 (the number to the left of :) if it isn't available; then, point JProfiler to that different port.
Looks like you are missing the general concept here.
It's nicely explained why to use containers in the official documentation.
The New Way is to deploy containers based on operating-system-level virtualization rather than hardware virtualization. These containers are isolated from each other and from the host: they have their own filesystems, they can’t see each others’ processes, and their computational resource usage can be bounded. They are easier to build than VMs, and because they are decoupled from the underlying infrastructure and from the host filesystem, they are portable across clouds and OS distributions.
Of course you don't need to install the libraries on each containers separately.
Kubernetes is using Volumes to share files between Containers.
So you can create a local type of Volume with JProfiles libs inside.
A local volume represents a mounted local storage device such as a disk, partition or directory.
You also need to keep in mind that if you share the Volume between Pods, those Pods will not know about JProfiles libs being attached. You will need to configure the Pod with correct environment variables/files through the use of Secrets or ConfigMaps.
You can configure your Pod to pull values from a Secret:
apiVersion: v1
kind: Pod
metadata:
labels:
context: docker-k8s-lab
name: jp-pod
name: jp-pod
spec:
containers:
- image: k8s.gcr.io/busybox
name: jp
envFrom:
secretRef:
name: jp-secret
jp-secret.yaml
apiVersion: v1
kind: Secret
metadata:
name: jp-secret
type: Opaque
data:
JPAGENT_PATH="-agentpath:/usr/local/jprofiler10/bin/linux-x64/libjprofilerti.so=nowait"
I hope this helps you.
I'm trying to deploy Postgres on my Kubernetes cluster and I have been successful to do this, but then I don't know how I can import my data which are in csv format. I already have the scripts which gets the path to data and create a database in a local instance of postgres, but when I deploy postgres on Kubernetes cluster then those scripts wont work because I can't see those script inside the pod.
I was looking for a solution to execute the scripts from host to inside the pod, or I can expose the directory of scripts and data to postgres pod.
I've found the hostpath solution, but I don't know how to define multiple volumes for a deployment. (I'm using Rook cluster to provision the volume)
Maybe a way to define a hostpath volume alongside a Rook volume so I can have access to the scripts and csv files inside the hostpath and then create the database inside the Rook volume.
I don't know of this makes sense, but I would appreciate if someone help me with this.
If you're using the official docker image, or an image that is derived from it but didn't destroy its entrypoint, then they have documentation about /docker-entrypoint-initdb.d/*.sql, with the tl;dr as
kind: ConfigMap
spec:
import_csv.sql: |
COPY my_table FROM '/whatever/path/you/want.csv' FORMAT csv /* etc */
---
kind: Pod
spec:
containers:
- volumeMounts:
- name: my-initdb-configmap
mountPath: /docker-entrypoint-initdb.d
readOnly: true
# ...
type deal
I've been developing an app on my local laptop (Mac) with Minikube. Instead of packaging the code and files into the docker image, I use hostPath and volumeMount that points to the code/file directory on my Mac, so that I can avoid rebuilding the image every time.
Now I would like to do the same iterative testing with google cloud. What's the best way to "mount" my local code/file directory and run pods remotely on the cloud? I don't want to package the code into a docker image, push to dockerhub, and then pull from dockerhub on gcloud. My dockerhub is a free account and would expose my code.
You want:
You want to mount your local file system into your remote Kubernetes cluster.
Answer:
As far I know, you can't do this. Its possible in minikube, because, you can mount your local directory with minikube.
Solution:
I can tell you an alternative way. May be this is not what you want. But it can help you.
Do you use git? If your answer is yes and also if you have no problem to keep your files into git repository, following process will help you.
spec:
containers:
- image: nginx
name: nginx
volumeMounts:
- mountPath: /mypath
name: git-volume
volumes:
- name: git-volume
gitRepo:
repository: "git#somewhere:me/my-git-repository.git"
revision: "22f1d8406d464b0c0874075539c1f2e96c253775"
When you will create this Pod, my-git-repository will be mounted into your directory /mypath inside your Pod container.
Basically, you can tell your Pod to pull this git from specific branch. So every time, you change your code, push it. Then create Pod again.
Read volumes/#gitrepo
Easiest method to replicate your setup would be to use a storage bucket for the mount point.
For your setup, just pull the code to the local host when needing to build from the storage bucket. I am assuming you have a build script to do the configuration part.
However as per the other comment, you could just use gcr to host your config files and use deployment manager to build.
Steps for using the Google Cloud Registry:
Build Docker Image
docker build -t <image-name>:<tag> <path-to-dockerfile>
Tag for GCloud Container Registry
docker tag <image-name>:<tag> us.gcr.io/<gcloud-project-id>/<image-name>:<tag>
Container Registry
gcloud docker -- push us.gcr.io/<gcloud-project-id>/<image-name>:<tag>
Your spec will then point to the container registry path:
spec:
containers:
- name: hello-world
image: us.gcr.io/<gcloud-project-id>/<image-name>:<tag>
ports:
- name: http
containerPort: 8080
I have a K8S cluster running on DigitalOcean. I have a Postgresql database running there and I want to create a volume using the DigitalOcean BlockStorage to be used by the Postgresql pod as volume. Is there any examples on how to do that?
If it's not possible to use DigitalOcean blockstorage then how do most companies run their persistence storage for databases?
No official support yet. You can try the example from someone in this github issue:
Update: I finished writing a volume plugin for digitalocean. Attach/detach is working on my cluster. Looking for anyone willing to
test this on their k8s digitalocean cluster. My branch is
https://github.com/wardviaene/kubernetes/tree/do-volume
You can use the following spec in your pod yml:
spec:
containers:
- name: k8s-demo
image: yourimage
volumeMounts:
- mountPath: /myvol
name: myvolume
ports:
- containerPort: 3000
volumes:
- name: myvolume
digitaloceanVolume:
volumeID: mykubvolume
fsType: ext4 Where mykubvolume is the volume created in DigitalOcean in the same region.
You will need to add create a config file:
[Global] apikey = do-api-key region = your-region and add these
parameters to your kubernetes processes: --cloud-provider=digitalocean
--cloud-config=/etc/cloud.config
I'm still waiting for an issue in the godo driver to be resolved,
before I can submit a PR (digitalocean/godo#102)
I found this link here about flexvolumes This mentions how you can customize to load vendor volumes. There is also a script on how to do this at script
A Container Storage Interface (CSI) Driver for DigitalOcean Block Storage.
https://github.com/digitalocean/csi-digitalocean
Have tested with statefulset MySql, working fine