Kubernetes and Docker¶
Contribution by Arco van Geest
Warning
This page is under heavy construction. Use at your own risk!
Docker¶
This is not needed for kubernetes but a lot of container development is still done with docker and docker-compose.
Containers¶
When a container is created with defaults it gets a name like nifty_fermat.
# only show running containers
$ docker ps
# only show all containers
$ docker ps -a
# remove containers
$ docker rm gifted_haibt friendly_curran
Images¶
# show images
$ docker images
<none> are old images where the tag has been reused for a new image.
# remove images by name or by id (that are not used in a container)
$ docker rmi testimage
$ docker rmi 76a9ddbe28e2
# remove all dangling images (DANGER!)
$docker images --filter "dangling=true" -q --no-trunc
Docker testing¶
System updates¶
Better stop the docker engine before applying updates. Sometimes containers stop working
Podman/Buildah¶
On newer RHEL like systems docker has been replaced by podman. In most cases it’s enough to replace the docker command by podman, e.g. podman ps
Kubernetes¶
Clients¶
Openshift Client (oc)¶
When installing the openshift client (OC) kubectl is also installed.
Choose openid-keycloak to connect, not kube:admin. The link can be found at “Help→Command Line Tools”
Get kubeconfig
$ export KUBECONFIG=~/.kube/openshiftconfig
$ oc login --token=TOKEN --server=https://api.ocp4.k8s.tudelft.nl:443
$ cat ~/.kube/openshiftconfig
Kubernetes control (kubectl)¶
Helm¶
Helm is very version strict. At least the Helm 2 versions. Helm 2 needs a lot of rights. Helm 3 is better to use as a non-admin user.
- untested
Kubernetes testing¶
run ad-hoc pods
port forward
Namespaces¶
create
non-root
context
warning
unique
naming convention
Storage¶
Backups¶
Backups are created with velero.
annotation
pod/deployment
Ingress¶
Retrieved from https://wiki.tudelft.ninja/index.phptitle=KubernetesUserInfo&oldid=317