Docker
In this guide we will create a Kubernetes cluster in Docker, using a containerized version of Talos.
Running Talos in Docker is intended to be used in CI pipelines, and local testing when you need a quick and easy cluster. Furthermore, if you are running Talos in production, it provides an excellent way for developers to develop against the same version of Talos.
Requirements
The follow are requirements for running Talos in Docker:
- Docker 18.03 or greater
- a recent version of
talosctl
Note
If you are using Docker Desktop on a macOS computer, and you encounter the error: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running? you may need to manually create the link for the Docker socket:sudo ln -s "$HOME/.docker/run/docker.sock" /var/run/docker.sock
Caveats
Due to the fact that Talos will be running in a container, certain APIs are not available.
For example upgrade
, reset
, and similar APIs don’t apply in container mode.
Further, when running on a Mac in docker, due to networking limitations, VIPs are not supported.
Create the Cluster
Creating a local cluster is as simple as:
talosctl cluster create
Once the above finishes successfully, your talosconfig
(~/.talos/config
) and kubeconfig
(~/.kube/config
) will be configured to point to the new cluster.
Note: Startup times can take up to a minute or more before the cluster is available.
Finally, we just need to specify which nodes you want to communicate with using talosctl. Talosctl can operate on one or all the nodes in the cluster – this makes cluster wide commands much easier.
talosctl config nodes 10.5.0.2 10.5.0.3
Talos and Kubernetes API are mapped to a random port on the host machine, the retrieved talosconfig
and kubeconfig
are configured automatically to point to the new cluster.
Talos API endpoint can be found using talosctl config info
:
$ talosctl config info
...
Endpoints: 127.0.0.1:38423
Kubernetes API endpoint is available with talosctl cluster show
:
$ talosctl cluster show
...
KUBERNETES ENDPOINT https://127.0.0.1:43083
Using the Cluster
Once the cluster is available, you can make use of talosctl
and kubectl
to interact with the cluster.
For example, to view current running containers, run talosctl containers
for a list of containers in the system
namespace, or talosctl containers -k
for the k8s.io
namespace.
To view the logs of a container, use talosctl logs <container>
or talosctl logs -k <container>
.
Cleaning Up
To cleanup, run:
talosctl cluster destroy
Multiple Clusters
Multiple Talos Linux cluster can be created on the same host, each cluster will need to have:
- a unique name (default is
talos-default
) - a unique network CIDR (default is
10.5.0.0/24
)
To create a new cluster, run:
talosctl cluster create --name cluster2 --cidr 10.6.0.0/24
To destroy a specific cluster, run:
talosctl cluster destroy --name cluster2
To switch between clusters, use --context
flag:
talosctl --context cluster2 version
kubectl --context admin@cluster2 get nodes
Running Talos in Docker Manually
To run Talos in a container manually, run:
docker run --rm -it \
--name tutorial \
--hostname talos-cp \
--read-only \
--privileged \
--security-opt seccomp=unconfined \
--mount type=tmpfs,destination=/run \
--mount type=tmpfs,destination=/system \
--mount type=tmpfs,destination=/tmp \
--mount type=volume,destination=/system/state \
--mount type=volume,destination=/var \
--mount type=volume,destination=/etc/cni \
--mount type=volume,destination=/etc/kubernetes \
--mount type=volume,destination=/usr/libexec/kubernetes \
--mount type=volume,destination=/opt \
-e PLATFORM=container \
ghcr.io/siderolabs/talos:v1.7.6
The machine configuration submitted to the container should have a host DNS feature enabled with forwardKubeDNSToHost
enabled.
It is used to forward DNS requests to the resolver provided by Docker (or other container runtime).