typhoon/digital-ocean/container-linux/kubernetes/cl/worker.yaml
Dalton Hubble eda78db08e Change Flatcar kubelet.service container from rkt to docker
* Use docker to run the `kubelet.service` container
* Update Kubelet mounts to match Fedora CoreOS
* Remove unused `/etc/ssl/certs` mount (see
https://github.com/poseidon/typhoon/pull/810)
* Remove unused `/usr/share/ca-certificates` mount
* Remove `/etc/resolv.conf` mount, Docker default is ok
* Change `delete-node.service` to use docker instead of rkt
and inline ExecStart, as was done on Fedora CoreOS
* Fix permission denied on shutdown `delete-node`, caused
by the kubeconfig mount changing with the introduction of
node TLS bootstrap

Background

* podmand, rkt, and runc daemonless container process runners
provide advantages over the docker daemon for system containers.
Docker requires workarounds for use in systemd units where the
ExecStart must tail logs so systemd can monitor the daemonized
container. https://github.com/moby/moby/issues/6791
* Why switch then? On Flatcar Linux, podman isn't shipped. rkt
works, but isn't developing while container standards continue
to move forward. Typhoon has used runc for the Kubelet runner
before in Fedora Atomic, but its more low-level. So we're left
with Docker, which is less than ideal, but shipped in Flatcar
* Flatcar Linux appears to be shifting system components to
use docker, which does provide some limited guards against
breakages (e.g. Flatcar cannot enable docker live restore)
2020-10-18 23:24:45 -07:00

118 lines
4.3 KiB
YAML

---
systemd:
units:
- name: docker.service
enabled: true
- name: locksmithd.service
mask: true
- name: kubelet.path
enabled: true
contents: |
[Unit]
Description=Watch for kubeconfig
[Path]
PathExists=/etc/kubernetes/kubeconfig
[Install]
WantedBy=multi-user.target
- name: wait-for-dns.service
enabled: true
contents: |
[Unit]
Description=Wait for DNS entries
Wants=systemd-resolved.service
Before=kubelet.service
[Service]
Type=oneshot
RemainAfterExit=true
ExecStart=/bin/sh -c 'while ! /usr/bin/grep '^[^#[:space:]]' /etc/resolv.conf > /dev/null; do sleep 1; done'
[Install]
RequiredBy=kubelet.service
- name: kubelet.service
contents: |
[Unit]
Description=Kubelet
Requires=docker.service
After=docker.service
Requires=coreos-metadata.service
After=coreos-metadata.service
Wants=rpc-statd.service
[Service]
Environment=KUBELET_IMAGE=quay.io/poseidon/kubelet:v1.19.3
EnvironmentFile=/run/metadata/coreos
ExecStartPre=/bin/mkdir -p /etc/kubernetes/cni/net.d
ExecStartPre=/bin/mkdir -p /etc/kubernetes/manifests
ExecStartPre=/bin/mkdir -p /opt/cni/bin
ExecStartPre=/bin/mkdir -p /var/lib/calico
ExecStartPre=/bin/mkdir -p /var/lib/kubelet/volumeplugins
ExecStartPre=/usr/bin/bash -c "grep 'certificate-authority-data' /etc/kubernetes/kubeconfig | awk '{print $2}' | base64 -d > /etc/kubernetes/ca.crt"
# Podman, rkt, or runc run container processes, whereas docker run
# is a client to a daemon and requires workarounds to use within a
# systemd unit. https://github.com/moby/moby/issues/6791
ExecStartPre=/usr/bin/docker run -d \
--name kubelet \
--privileged \
--pid host \
--network host \
-v /etc/kubernetes:/etc/kubernetes:ro \
-v /etc/machine-id:/etc/machine-id:ro \
-v /usr/lib/os-release:/etc/os-release:ro \
-v /lib/modules:/lib/modules:ro \
-v /run:/run \
-v /sys/fs/cgroup:/sys/fs/cgroup:ro \
-v /sys/fs/cgroup/systemd:/sys/fs/cgroup/systemd \
-v /var/lib/calico:/var/lib/calico:ro \
-v /var/lib/docker:/var/lib/docker \
-v /var/lib/kubelet:/var/lib/kubelet:rshared \
-v /var/log:/var/log \
-v /opt/cni/bin:/opt/cni/bin \
$${KUBELET_IMAGE} \
--anonymous-auth=false \
--authentication-token-webhook \
--authorization-mode=Webhook \
--bootstrap-kubeconfig=/etc/kubernetes/kubeconfig \
--client-ca-file=/etc/kubernetes/ca.crt \
--cluster_dns=${cluster_dns_service_ip} \
--cluster_domain=${cluster_domain_suffix} \
--cni-conf-dir=/etc/kubernetes/cni/net.d \
--healthz-port=0 \
--hostname-override=$${COREOS_DIGITALOCEAN_IPV4_PRIVATE_0} \
--kubeconfig=/var/lib/kubelet/kubeconfig \
--network-plugin=cni \
--node-labels=node.kubernetes.io/node \
--pod-manifest-path=/etc/kubernetes/manifests \
--read-only-port=0 \
--rotate-certificates \
--volume-plugin-dir=/var/lib/kubelet/volumeplugins
ExecStart=docker logs -f kubelet
ExecStop=docker stop kubelet
ExecStopPost=docker rm kubelet
Restart=always
RestartSec=5
[Install]
WantedBy=multi-user.target
- name: delete-node.service
enabled: true
contents: |
[Unit]
Description=Delete Kubernetes node on shutdown
[Service]
Environment=KUBELET_IMAGE=quay.io/poseidon/kubelet:v1.19.3
Type=oneshot
RemainAfterExit=true
ExecStart=/bin/true
ExecStop=/bin/bash -c '/usr/bin/docker run -v /var/lib/kubelet:/var/lib/kubelet:ro --entrypoint /usr/local/bin/kubectl $${KUBELET_IMAGE} --kubeconfig=/var/lib/kubelet/kubeconfig delete node $HOSTNAME'
[Install]
WantedBy=multi-user.target
storage:
directories:
- path: /etc/kubernetes
filesystem: root
mode: 0755
files:
- path: /etc/sysctl.d/max-user-watches.conf
filesystem: root
mode: 0644
contents:
inline: |
fs.inotify.max_user_watches=16184