Kata Containers with Cilium
Kata Containers is an open source project that
provides a secure container runtime with lightweight virtual machines that feel
and perform like containers, but provide stronger workload isolation using
hardware virtualization technology as a second layer of defense. Kata
Containers implements OCI runtime spec, just like runc that is used by
Docker. Cilium can be used along with Kata Containers, using both enables
higher degree of security. Kata Containers enhances security in the compute
layer, while Cilium provides policy and observability in the networking layer.
This guide shows how to install Cilium along with Kata Containers. It assumes that you have already followed the official Kata Containers installation user guide to get the Kata Containers runtime up and running on your platform of choice but that you haven’t yet setup Kubernetes.
Note
This guide has been validated by following the Kata Containers guide for Google Compute Engine (GCE) and using Ubuntu 18.04 LTS with the packaged version of Kata Containers, CRI-containerd and Kubernetes 1.18.3.
Setup Kubernetes with CRI
Kata Containers runtime is an OCI compatible runtime and cannot directly interact with the CRI API level. For this reason, it relies on a CRI implementation to translate CRI into OCI. At the time of writing this guide, there are two supported ways called CRI-O and CRI-containerd. It is up to you to choose the one that you want, but you have to pick one.
Refer to the section Requirements for detailed instruction on how to prepare your Kubernetes environment and make sure to use Kubernetes >= 1.12. Then, follow the official guide to run Kata Containers with Kubernetes.
Note
Minimum version of kubernetes 1.12 is required to use the RuntimeClass Feature for Kata Container runtime described below.
With your Kubernetes cluster ready, you can now proceed to deploy Cilium.
Deploy Cilium
Note
Make sure you have Helm 3 installed. Helm 2 is no longer supported.
Download the Cilium release tarball and change to the kubernetes install directory:
curl -LO https://github.com/cilium/cilium/archive/master.tar.gz tar xzf master.tar.gz cd cilium-master/install/kubernetes
Deploy Cilium release via Helm:
helm install cilium ./cilium \ --namespace kube-system \ --set containerRuntime.integration=criohelm install cilium ./cilium \ --namespace kube-system \ --set containerRuntime.integration=containerd
Warning
Kata containers do not work with the socket-level loadbalancer, or with
kube-proxy replacement in strict mode. These
features should be disabled with --set socketLB.enabled=false
(default) and --set kubeProxyReplacement=disabled (or partial).
Both features rely on socket-based load-balancing, which is not possible given that Kata containers are virtual machines running with their own kernel. For kube-proxy replacement, this limitation is tracked with GitHub issue 15437.
Validate the Installation
Install the latest version of the Cilium CLI. The Cilium CLI can be used to install Cilium, inspect the state of a Cilium installation, and enable/disable various features (e.g. clustermesh, Hubble).
CILIUM_CLI_VERSION=$(curl -s https://raw.githubusercontent.com/cilium/cilium-cli/master/stable.txt)
CLI_ARCH=amd64
if [ "$(uname -m)" = "aarch64" ]; then CLI_ARCH=arm64; fi
curl -L --fail --remote-name-all https://github.com/cilium/cilium-cli/releases/download/${CILIUM_CLI_VERSION}/cilium-linux-${CLI_ARCH}.tar.gz{,.sha256sum}
sha256sum --check cilium-linux-${CLI_ARCH}.tar.gz.sha256sum
sudo tar xzvfC cilium-linux-${CLI_ARCH}.tar.gz /usr/local/bin
rm cilium-linux-${CLI_ARCH}.tar.gz{,.sha256sum}
CILIUM_CLI_VERSION=$(curl -s https://raw.githubusercontent.com/cilium/cilium-cli/master/stable.txt)
CLI_ARCH=amd64
if [ "$(uname -m)" = "arm64" ]; then CLI_ARCH=arm64; fi
curl -L --fail --remote-name-all https://github.com/cilium/cilium-cli/releases/download/${CILIUM_CLI_VERSION}/cilium-darwin-${CLI_ARCH}.tar.gz{,.sha256sum}
shasum -a 256 -c cilium-darwin-${CLI_ARCH}.tar.gz.sha256sum
sudo tar xzvfC cilium-darwin-${CLI_ARCH}.tar.gz /usr/local/bin
rm cilium-darwin-${CLI_ARCH}.tar.gz{,.sha256sum}
See the full page of releases.
To validate that Cilium has been properly installed, you can run
$ cilium status --wait
/¯¯\
/¯¯\__/¯¯\ Cilium: OK
\__/¯¯\__/ Operator: OK
/¯¯\__/¯¯\ Hubble: disabled
\__/¯¯\__/ ClusterMesh: disabled
\__/
DaemonSet cilium Desired: 2, Ready: 2/2, Available: 2/2
Deployment cilium-operator Desired: 2, Ready: 2/2, Available: 2/2
Containers: cilium-operator Running: 2
cilium Running: 2
Image versions cilium quay.io/cilium/cilium:v1.9.5: 2
cilium-operator quay.io/cilium/operator-generic:v1.9.5: 2
Run the following command to validate that your cluster has proper network connectivity:
$ cilium connectivity test
ℹ️ Monitor aggregation detected, will skip some flow validation steps
✨ [k8s-cluster] Creating namespace for connectivity check...
(...)
---------------------------------------------------------------------------------------------------------------------
📋 Test Report
---------------------------------------------------------------------------------------------------------------------
✅ 69/69 tests successful (0 warnings)
Congratulations! You have a fully functional Kubernetes cluster with Cilium. 🎉
You can monitor as Cilium and all required components are being installed:
$ kubectl -n kube-system get pods --watch
NAME READY STATUS RESTARTS AGE
cilium-operator-cb4578bc5-q52qk 0/1 Pending 0 8s
cilium-s8w5m 0/1 PodInitializing 0 7s
coredns-86c58d9df4-4g7dd 0/1 ContainerCreating 0 8m57s
coredns-86c58d9df4-4l6b2 0/1 ContainerCreating 0 8m57s
It may take a couple of minutes for all components to come up:
cilium-operator-cb4578bc5-q52qk 1/1 Running 0 4m13s
cilium-s8w5m 1/1 Running 0 4m12s
coredns-86c58d9df4-4g7dd 1/1 Running 0 13m
coredns-86c58d9df4-4l6b2 1/1 Running 0 13m
You can deploy the “connectivity-check” to test connectivity between pods. It is recommended to create a separate namespace for this.
kubectl create ns cilium-test
Deploy the check with:
kubectl apply -n cilium-test -f https://raw.githubusercontent.com/cilium/cilium/HEAD/examples/kubernetes/connectivity-check/connectivity-check.yaml
It will deploy a series of deployments which will use various connectivity paths to connect to each other. Connectivity paths include with and without service load-balancing and various network policy combinations. The pod name indicates the connectivity variant and the readiness and liveness gate indicates success or failure of the test:
$ kubectl get pods -n cilium-test
NAME READY STATUS RESTARTS AGE
echo-a-76c5d9bd76-q8d99 1/1 Running 0 66s
echo-b-795c4b4f76-9wrrx 1/1 Running 0 66s
echo-b-host-6b7fc94b7c-xtsff 1/1 Running 0 66s
host-to-b-multi-node-clusterip-85476cd779-bpg4b 1/1 Running 0 66s
host-to-b-multi-node-headless-dc6c44cb5-8jdz8 1/1 Running 0 65s
pod-to-a-79546bc469-rl2qq 1/1 Running 0 66s
pod-to-a-allowed-cnp-58b7f7fb8f-lkq7p 1/1 Running 0 66s
pod-to-a-denied-cnp-6967cb6f7f-7h9fn 1/1 Running 0 66s
pod-to-b-intra-node-nodeport-9b487cf89-6ptrt 1/1 Running 0 65s
pod-to-b-multi-node-clusterip-7db5dfdcf7-jkjpw 1/1 Running 0 66s
pod-to-b-multi-node-headless-7d44b85d69-mtscc 1/1 Running 0 66s
pod-to-b-multi-node-nodeport-7ffc76db7c-rrw82 1/1 Running 0 65s
pod-to-external-1111-d56f47579-d79dz 1/1 Running 0 66s
pod-to-external-fqdn-allow-google-cnp-78986f4bcf-btjn7 1/1 Running 0 66s
Note
If you deploy the connectivity check to a single node cluster, pods that check multi-node
functionalities will remain in the Pending state. This is expected since these pods
need at least 2 nodes to be scheduled successfully.
Once done with the test, remove the cilium-test namespace:
kubectl delete ns cilium-test
Run Kata Containers with Cilium CNI
Now that your Kubernetes cluster is configured with the Kata Containers runtime and Cilium as the CNI, you can run a sample workload by following these instructions.