I'm trying to deploy a react app on my local machine with docker-desktop and its kubernetes cluster with bitnami apache helm chart.
I'm following this this tutorial.
The tutorial makes you publish the image on a public repo (step 2) and I don't want to do that. It is indeed possible to pass the app files through a persistent volume claim.
This is described in the following tutorial.
Step 2 of this second tutorial lets you create a pod pointing to a PVC and then asks you to copy the app files there by using command
kubectl cp /myapp/* apache-data-pod:/data/
My issues:
I cannot use the * wildcard or else I get an error. To avoid this I just run
kubectl cp . apache-data-pod:/data/
This instruction copies the files in the pod but it creates another data folder in the already existing data folder in the pod filesystem
After this command my pod filesystem looks like this
I tried executing
kubectl cp . apache-data-pod:/
But this copies the file in the root of the pod filesystem at the same location where first data folder is.
I need to copy the data directly in <my_pod>:/data/.
How can I achieve such behaviour?
Regards
**Use the full path in the command as mentioned below to copy local files to POD : *
kubectl cp apache-pod:/var/www/html/index.html /tmp
*If there are multiple containers on the POD, Use the below syntax to copy a file from local to pod:
kubectl cp /<path-to-your-file>/<file-name> <pod-name>:<fully-qualified-file-name> -c <container-name>
Points to remember :
While referring to the file path on the POD. It is always relative to the WORKDIR you have defined on your image.
Unlike Linux, the base directory does not always start from the / workdir is the base directory
When you have multiple containers on the POD you need to specify the container to use with the copy operation using -c parameter
Quick Example of kubectl cp : Here is the command to copy the index.html file from the POD’s /var/www/html to the local /tmp directory.
No need to mention the full path, when the doc root is the workdir or the default directory of the image.
kubectl cp apache-pod:index.html /tmp
To make it less confusing, you can always write the full path like this
kubectl cp apache-pod:/var/www/html/index.html /tmp
*Also refer to this stack question for more information.
I am using k3d to run local kubernetes
I have created a cluster using k3d.
Now I want to mount a local directory as a persistent volume.
How can i do this while using k3d.
I know in minikube
$ minikube start --mount-string="$HOME/go/src/github.com/nginx:/data" --mount
Then If you mount /data into your Pod using hostPath, you will get you local directory data into Pod.
Is there any similar technique here also while using k3d
According to the answers to this Github question the teature you're looking for is not available yet.
Here is some idea from this link:
The simplest I guess would be to have a pretty generic mount containing all the code, e.g. in my case, I could do k3d cluster create -v "$HOME/git:/git#agent:*" to get all the repositories on my host present in all agent nodes to be used for hot-reloading.
According to this documentation one can use the following command with the adequate flag:
k3d cluster create NAME -v [SOURCE:]DEST[#NODEFILTER[;NODEFILTER...]]
This command mounts volumes into the nodes
(Format:[SOURCE:]DEST[#NODEFILTER[;NODEFILTER...]]
Example:
`k3d cluster create --agents 2 -v /my/path#agent:0,1 -v /tmp/test:/tmp/other#server:0`
Here is also an interesting article how volumes and storage work in a K3s cluster (with examples).
I think this feature is not yet available
https://github.com/k3d-io/k3d/issues/566
So far we can only mount volumn when we create a new cluster.
k3d cluster create mykube --volume HOME/go/src/github.com/nginx:/data
I have AKS cluster deployed(version 1.19) on Azure, part of the deployment in kube-system namespace there are 2 azure-cni-networkmonitor pods, when opening a bash in one of the pods using:
kubectl exec -t -i -n kube-system azure-cni-networkmonitor-th6pv -- bash
I've noticed that although I'm running as root in the container:
uid=0(root) gid=0(root) groups=0(root)
There are some files that I can't open for reading, read commands are resulting in permission denied error, for example:
cat: /run/containerd/io.containerd.runtime.v1.linux/k8s.io/c3bd2dfc2ad242e1a706eb3f42be67710630d314cfeb4b96ec35f35869264830/rootfs/sys/module/zswap/uevent: Permission denied
File stat:
Access: (0200/--w-------) Uid: ( 0/ root) Gid: ( 0/ root)
Linux distribution running on container:
Common Base Linux Delridge
Although the file is non-readable, I shouldn't have a problem to read it as root right?
Any idea why would this happen? I don't see there any SELinux enabled.
/proc and /sys are special filesystems created and maintained by the kernel to provide interfaces into settings and events in the system. The uevent files are used to access information about the devices or send events.
If a given subsystem implements functionality to expose information via that interface, you can cat the file:
[root#home sys]# cat /sys/devices/system/cpu/cpu0/uevent
DRIVER=processor
MODALIAS=cpu:type:x86,ven0000fam0006mod003F:feature:,0000,0001,0002,0003,0004,0005,0006,0007,0008,0009,000B,000C,000D,000E,000F,0010,0011,0013,0017,0018,0019,001A,001B,001C,002B,0034,003A,003B,003D,0068,006F,0070,0072,0074,0075,0076,0079,0080,0081,0089,008C,008D,0091,0093,0094,0096,0097,0099,009A,009B,009C,009D,009E,009F,00C0,00C5,00E7,00EB,00EC,00F0,00F1,00F3,00F5,00F6,00F9,00FA,00FB,00FD,00FF,0120,0123,0125,0127,0128,0129,012A,012D,0140,0165,024A,025A,025B,025C,025D,025F
But if that subsystem doesn't expose that interface, you just get permission denied - even root can't call kernel code that's not there.
I'm attempting to write MLflow artifacts to an NFS-mounted PVC. It's a new PVC mounting at /opt/mlflow, but MLflow seems to have permission writing to it. The specific error I'm getting is
PermissionError: [Errno 13] Permission denied: '/opt/mlflow'
I ran the same deployment with an S3-backed artifact store, and that worked just fine. That was on my home computer though, and I don't have the ability to do that at work. The MLflow documentation seems to indicate that I don't need any special syntax for NFS mounts.
Independent of MLflow you can approach this in a standard file permission way.
Exec into your pod and view the permissions at that file path
kubectl exec -it <pod>
ls -l /opt/mlflow
Within your pod/container see what user you are running as
whoami
If your user doesn't have access to that filepath, then you could adjust the file permissions by mounting the pvc into a different pod that runs under a user with permission to adjust them. Or you could try using fsGroup to control the permissions of the files mounted, which you can read more about here.
I'm using docker-compose in one of my projects. During development i mount my source directory to a volume in one of my docker services for easy development. At the same time, I have a db service (psql) that mounts a named volume for persistent data storage.
I start by solution and everything is working fine
$ docker-compose up -d
When I check my volumes I see the named and "unnamed" (source volume).
$ docker volume ls
DRIVER VOLUME NAME
local 226ba7af9689c511cb5e6c06ceb36e6c26a75dd9d619360882a1012cdcd25b72
local myproject_data
The problem I experience is that, when I do
$ docker-compose down
...
$ docker volume ls
DRIVER VOLUME NAME
local 226ba7af9689c511cb5e6c06ceb36e6c26a75dd9d619360882a1012cdcd25b72
local myproject_data
both volumes remain. Every time I run
$ docker-compose down
$ docker-compose up -d
a new volume is created for my source mount
$ docker volume ls
DRIVER VOLUME NAME
local 19181286b19c0c3f5b67d7d1f0e3f237c83317816acbdf4223328fdf46046518
local 226ba7af9689c511cb5e6c06ceb36e6c26a75dd9d619360882a1012cdcd25b72
local myproject_data
I know that this will not happen on my deployment server, since it will not mount the source, but is there a way to not make the mounted source persistent?
You can use the --rm option in docker run. To use it with docker-compose you can use
docker-compose rm -v after stopping your containers with docker-compose stop
If you go through the docs about Data volumes , its mentioned that
Data volumes persist even if the container itself is deleted.
So that means, stopping a container will not remove the volumes it created, whether named or anonymous.
Now if you read further down to Removing volumes
A Docker data volume persists after a container is deleted. You can
create named or anonymous volumes. Named volumes have a specific
source form outside the container, for example awesome:/bar. Anonymous
volumes have no specific source. When the container is deleted, you
should instruct the Docker Engine daemon to clean up anonymous
volumes. To do this, use the --rm option, for example:
$ docker run --rm -v /foo -v awesome:/bar busybox top
This command creates an anonymous /foo volume. When the container is
removed, the Docker Engine removes the /foo volume but not the awesome
volume.
Just remove volumes with the down command:
docker-compose down -v