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kata-deploy

kata-deploy provides a Dockerfile, which contains all of the binaries and artifacts required to run Kata Containers, as well as reference DaemonSets, which can be utilized to install Kata Containers on a running Kubernetes cluster.

Note, installation through DaemonSets successfully installs katacontainers.io/kata-runtime on a node only if it uses either containerd or CRI-O CRI-shims.

Kubernetes quick start

Install Kata on a running Kubernetes cluster

$ cd $GOPATH/src/github.com/kata-containers/kata-containers/tools/packaging/kata-deploy
$ kubectl apply -f kata-rbac/base/kata-rbac.yaml
$ kubectl apply -f kata-deploy/base/kata-deploy.yaml

or on a k3s cluster:

$ cd $GOPATH/src/github.com/kata-containers/kata-containers/tools/packaging/kata-deploy
$ kubectl apply -k kata-deploy/overlays/k3s

Run a sample workload

Workloads specify the runtime they'd like to utilize by setting the appropriate runtimeClass object within the Pod specification. The runtimeClass examples provided define a node selector to match node label katacontainers.io/kata-runtime:"true", which will ensure the workload is only scheduled on a node that has Kata Containers installed

runtimeClass is a built-in type in Kubernetes. To apply each Kata Containers runtimeClass:

  $ cd $GOPATH/src/github.com/kata-containers/kata-containers/tools/packaging/kata-deploy/runtimeclasses
  $ kubectl apply -f kata-runtimeClasses.yaml

The following YAML snippet shows how to specify a workload should use Kata with Cloud Hypervisor:

spec:
  template:
    spec:
      runtimeClassName: kata-clh

The following YAML snippet shows how to specify a workload should use Kata with Firecracker:

spec:
  template:
    spec:
      runtimeClassName: kata-fc

The following YAML snippet shows how to specify a workload should use Kata with QEMU:

spec:
  template:
    spec:
      runtimeClassName: kata-qemu

To run an example with kata-clh:

$ cd $GOPATH/src/github.com/kata-containers/kata-containers/tools/packaging/kata-deploy/examples
$ kubectl apply -f test-deploy-kata-clh.yaml

To run an example with kata-fc:

$ cd $GOPATH/src/github.com/kata-containers/kata-containers/tools/packaging/kata-deploy/examples
$ kubectl apply -f test-deploy-kata-fc.yaml

To run an example with kata-qemu:

$ cd $GOPATH/src/github.com/kata-containers/kata-containers/tools/packaging/kata-deploy/examples
$ kubectl apply -f test-deploy-kata-qemu.yaml

The following removes the test pods:

$ cd $GOPATH/src/github.com/kata-containers/kata-containers/tools/packaging/kata-deploy/examples
$ kubectl delete -f test-deploy-kata-clh.yaml
$ kubectl delete -f test-deploy-kata-fc.yaml
$ kubectl delete -f test-deploy-kata-qemu.yaml

Remove Kata from the Kubernetes cluster

$ cd $GOPATH/src/github.com/kata-containers/kata-containers/tools/packaging/kata-deploy
$ kubectl delete -f kata-deploy/base/kata-deploy.yaml
$ kubectl apply -f kata-cleanup/base/kata-cleanup.yaml
$ kubectl delete -f kata-cleanup/base/kata-cleanup.yaml
$ kubectl delete -f kata-rbac/base/kata-rbac.yaml
$ kubectl delete -f runtimeclasses/kata-runtimeClasses.yaml

kata-deploy details

Dockerfile

The Dockerfile used to create the container image deployed in the DaemonSet is provided here. This image contains all the necessary artifacts for running Kata Containers, all of which are pulled from the Kata Containers release page.

Host artifacts:

  • cloud-hypervisor, firecracker, qemu-system-x86_64, and supporting binaries
  • containerd-shim-kata-v2
  • kata-collect-data.sh
  • kata-runtime

Virtual Machine artifacts:

  • kata-containers.img and kata-containers-initrd.img: pulled from Kata GitHub releases page
  • vmlinuz.container and vmlinuz-virtiofs.container: pulled from Kata GitHub releases page

DaemonSets and RBAC

Two DaemonSets are introduced for kata-deploy, as well as an RBAC to facilitate applying labels to the nodes.

Kata deploy

This DaemonSet installs the necessary Kata binaries, configuration files, and virtual machine artifacts on the node. Once installed, the DaemonSet adds a node label katacontainers.io/kata-runtime=true and reconfigures either CRI-O or containerd to register three runtimeClasses: kata-clh (for Cloud Hypervisor isolation), kata-qemu (for QEMU isolation), and kata-fc (for Firecracker isolation). As a final step the DaemonSet restarts either CRI-O or containerd. Upon deletion, the DaemonSet removes the Kata binaries and VM artifacts and updates the node label to katacontainers.io/kata-runtime=cleanup.

Kata cleanup

This DaemonSet runs of the node has the label katacontainers.io/kata-runtime=cleanup. These DaemonSets removes the katacontainers.io/kata-runtime label as well as restarts either CRI-O or containerd systemctl daemon. You cannot execute these resets during the preStopHook of the Kata installer DaemonSet, which necessitated this final cleanup DaemonSet.