infra/modules/create-template-vm/k8s-node-containerd-setup.sh
Viktor Barzin 8ed427a7e4 cloud-init: hands-off k8s worker provisioning + 5 bug fixes
Goal: re-clone the worker template, boot, and have it appear as `kubectl
get nodes …Ready` with no manual steps. Adds `scripts/provision-k8s-worker
NAME VMID IP` and rebuilds the cloud-init pipeline that was failing five
distinct ways on a clean boot.

Bugs fixed (all hit during the k8s-node5 + k8s-node6 builds today):

1. `indent(6, containerd_config_update_command)` indented the bodies of
   `cat >> /etc/containerd/config.toml <<'CONTAINERD_GC'` heredocs, so
   [plugins.*] TOML sections landed in /etc/containerd/config.toml at
   col 6 — containerd refused to parse them. Source is now a normal
   .sh file (`modules/create-template-vm/k8s-node-containerd-setup.sh`)
   base64-embedded into `write_files`; YAML whitespace never touches
   the heredoc bodies.

2. The same script tried to `cat >> /etc/containerd/config.toml`
   `[plugins."io.containerd.gc.v1.scheduler"]` etc., which containerd
   v2.2.4's `config default` ALREADY emits. Result: `toml: table …
   already exists`. Patched with sed-in-place overrides instead.

3. Kubelet tuning (sed against /var/lib/kubelet/config.yaml) ran from
   the containerd setup script — BEFORE `kubeadm join` writes that
   file. Sed aborted with "No such file or directory", `set -e` killed
   the script, post-script cloud-init steps kept going (cloud-init
   doesn't stop on runcmd failure). Split into a dedicated
   `k8s-node-post-join-tune.sh` invoked AFTER kubeadm join.

4. cloud_init.yaml fallocate'd a 4G swapfile and `swapon`'d it BEFORE
   kubeadm join. kubelet defaults to failSwapOn=true → exited 1
   immediately. Replaced the swap setup with `swapoff -a` (node4
   already runs this way and the cluster is fine).

5. Without `hostname:` in the shared user-data snippet, Proxmox's
   auto-generated meta-data does NOT include local-hostname when
   `cicustom user=…` is set — so cloud-init falls back to the cloud
   image's default `ubuntu` and `kubeadm join` registers the wrong
   node name. `provision-k8s-worker` now writes a per-node
   `<NAME>-meta.yaml` snippet and passes both via
   `cicustom user=…,meta=…`.

Other improvements rolled in while fixing the above:

- `ssh_public_key` read from Vault (`secret/viktor.ssh_public_key`,
  added today) instead of `var.ssh_public_key`. The last
  `terragrunt apply` was run with that var empty, leaving the snippet's
  `ssh_authorized_keys` with a single blank entry; the wizard user
  was effectively locked out of every fresh node.
- `cloud_init.yaml` adds `/etc/systemd/resolved.conf.d/global-dns.conf`
  with `DNS=8.8.8.8 1.1.1.1, FallbackDNS=10.0.20.201`. Without it,
  systemd-resolved only consulted Technitium (link-level), which
  returns NXDOMAIN for `forgejo.viktorbarzin.me` — kubelet pulls from
  the Forgejo registry then failed DNS until I patched it manually
  on node5.
- k8s apt repo bumped v1.32 → v1.34 (matches cluster).
- The containerd setup script now creates hosts.toml for forgejo,
  quay, registry.k8s.io in addition to docker.io + ghcr.io. node3/4
  had these added by hand post-bootstrap; now they're baked in.
- `config_path` sed matches both `""` (containerd v1) and `''`
  (containerd v2.x). Without the v2 match, the certs.d mirror dir was
  silently ignored.
- `proxmox-csi` node map adds k8s-node5 + k8s-node6 entries so CSI
  topology labels (region/zone, max-volume-attachments=28) apply on
  next `tg apply`.
- `stacks/infra/main.tf` shed the 160-line inline containerd setup
  heredoc — that whole thing now lives in the module as a .sh file.

Known unsolved gaps (deferred):

- iscsid restart hangs ~90s on first boot before SIGKILL releases it
  (systemd-resolved restart kicks iscsid via dependency). Adds wall-
  clock time but doesn't block the join.
- `provision-k8s-worker` doesn't run `tg apply` on `proxmox-csi`
  afterward, so the CSI topology labels need a manual apply after
  the node joins. Solving cleanly needs the CSI map to derive from
  `kubectl get nodes` instead of a static local — separate work.
- `var.containerd_config_update_command` is now ignored when
  is_k8s_template=true (replaced by the bundled .sh file). Variable
  kept with a deprecation note to avoid breaking other call sites.

E2E proof: k8s-node6 (VMID 206) boots hands-off from
`provision-k8s-worker k8s-node6 206 10.0.20.106` and appears as
`kubectl get nodes …Ready` ~7 min later (most of which is the apt
package_upgrade — separate optimization).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-26 11:52:00 +00:00

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#!/usr/bin/env bash
#
# K8s node containerd + kubelet bootstrap. Runs once via cloud-init runcmd.
# Embedded into the cloud-init snippet base64-encoded by main.tf so YAML
# whitespace handling never touches the heredoc bodies — TOML / Python
# blocks below land in /etc/containerd/config.toml etc. with their leading
# whitespace intact.
#
# Layout:
# 1. /etc/containerd/config.toml — config_path + mirror dirs + GC tuning
# 2. /etc/containerd/certs.d/*/hosts.toml — per-registry mirror configs
# 3. /var/lib/kubelet/config.yaml — eviction + shutdown grace + log rotation
# 4. /etc/systemd/logind.conf.d + kubelet.service.d — graceful shutdown
# 5. (master-only) /etc/kubernetes/manifests — apiserver + controller flags
set -euo pipefail
# 1. config_path — match BOTH quote styles. containerd v1 writes `""`,
# containerd v2.x writes `''`. Without the v2 match, hosts.toml mirror
# config is silently ignored — observed 2026-05-26 on k8s-node4
# (containerd v2.2.4) and reproduced on k8s-node5 v1 boot.
sed -i "s|config_path = \"\"|config_path = \"/etc/containerd/certs.d\"|g" /etc/containerd/config.toml
sed -i "s|config_path = ''|config_path = \"/etc/containerd/certs.d\"|g" /etc/containerd/config.toml
# 2. Per-registry hosts.toml — pull-through caches on docker-registry VM
# (10.0.20.10) for high-traffic registries, Traefik LB (10.0.20.200) for
# forgejo. Low-traffic registries (registry.k8s.io, reg.kyverno.io) skip
# the cache and pull direct because past pull-through cache attempts
# truncated downloads and broke VPA certgen + Kyverno image pulls.
mkdir -p /etc/containerd/certs.d/docker.io
cat > /etc/containerd/certs.d/docker.io/hosts.toml <<'DOCKERIO'
server = "https://registry-1.docker.io"
[host."http://10.0.20.10:5000"]
capabilities = ["pull", "resolve"]
[host."https://registry-1.docker.io"]
capabilities = ["pull", "resolve"]
DOCKERIO
mkdir -p /etc/containerd/certs.d/ghcr.io
cat > /etc/containerd/certs.d/ghcr.io/hosts.toml <<'GHCR'
server = "https://ghcr.io"
[host."http://10.0.20.10:5010"]
capabilities = ["pull", "resolve"]
[host."https://ghcr.io"]
capabilities = ["pull", "resolve"]
GHCR
# Forgejo OCI registry: prefer in-cluster Traefik LB (10.0.20.200) to
# avoid hairpin NAT. Traefik serves the *.viktorbarzin.me wildcard so
# SNI verification succeeds. If the mirror is unreachable, fall back to
# public DNS resolution (needs the global DNS fallback set up below).
mkdir -p /etc/containerd/certs.d/forgejo.viktorbarzin.me
cat > /etc/containerd/certs.d/forgejo.viktorbarzin.me/hosts.toml <<'FORGEJO'
server = "https://forgejo.viktorbarzin.me"
[host."https://10.0.20.200"]
capabilities = ["pull", "resolve"]
FORGEJO
# quay.io + registry.k8s.io: include mirror configs that match node4's
# layout (no real pull-through cache today, server line is the direct
# upstream). Keeping these present makes the per-node config uniform and
# lets us flip a cache on later by editing only the [host."..."] block.
mkdir -p /etc/containerd/certs.d/quay.io
cat > /etc/containerd/certs.d/quay.io/hosts.toml <<'QUAY'
server = "https://quay.io"
[host."http://10.0.20.10:5020"]
capabilities = ["pull", "resolve"]
QUAY
mkdir -p /etc/containerd/certs.d/registry.k8s.io
cat > /etc/containerd/certs.d/registry.k8s.io/hosts.toml <<'K8SREG'
server = "https://registry.k8s.io"
[host."http://10.0.20.10:5030"]
capabilities = ["pull", "resolve"]
K8SREG
# 3. containerd tuning: parallel pulls + selective GC overrides.
# containerd v2's `config default` ALREADY emits `[plugins.'io.containerd.gc.v1.scheduler']`,
# `[plugins.'io.containerd.runtime.v2.task']`, and `[plugins.'io.containerd.metadata.v1.bolt']`
# sections — declaring them again fails with `toml: table … already exists`
# (observed on node6 boot 2026-05-26). Patch values in place instead.
sed -i 's/.*max_concurrent_downloads = 3/max_concurrent_downloads = 20/g' /etc/containerd/config.toml
# pause_threshold: 0.5 → 0.02 (run GC more aggressively when images dirty %)
sed -i "s/^[[:space:]]*pause_threshold = .*/ pause_threshold = 0.02/" /etc/containerd/config.toml
# schedule_delay: 0s/1ms → 30 min (longer cool-down between GC runs)
sed -i "s/^[[:space:]]*schedule_delay = .*/ schedule_delay = '1800s'/" /etc/containerd/config.toml
# exit_timeout: 0s → 5m (more aggressive container cleanup)
sed -i "s/^[[:space:]]*exit_timeout = .*/ exit_timeout = '5m'/" /etc/containerd/config.toml
# 4. (kubelet tuning intentionally NOT here — /var/lib/kubelet/config.yaml
# only exists AFTER kubeadm join. That work runs in
# k8s-node-post-join-tune.sh, invoked as a separate cloud-init runcmd
# step after the join completes.)
# 5. logind + kubelet systemd unit — total kubelet shutdown 310s, so
# logind InhibitDelay > that and kubelet TimeoutStopSec > that.
mkdir -p /etc/systemd/logind.conf.d
cat > /etc/systemd/logind.conf.d/kubelet-shutdown.conf <<'LOGIND_CONF'
[Login]
InhibitDelayMaxSec=480
LOGIND_CONF
systemctl restart systemd-logind
mkdir -p /etc/systemd/system/kubelet.service.d
cat > /etc/systemd/system/kubelet.service.d/20-shutdown.conf <<'KUBELET_SHUTDOWN'
[Service]
TimeoutStopSec=420s
KUBELET_SHUTDOWN
systemctl daemon-reload
# 6. (master-only) faster pod eviction + attach-detach reconcile.
if [ -f /etc/kubernetes/manifests/kube-controller-manager.yaml ]; then
python3 - <<'CM_PATCH'
import yaml
with open('/etc/kubernetes/manifests/kube-controller-manager.yaml') as f:
m = yaml.safe_load(f)
args = m['spec']['containers'][0]['command']
for flag in ['--attach-detach-reconcile-sync-period=15s']:
key = flag.split('=')[0]
args = [a for a in args if not a.startswith(key)]
args.append(flag)
m['spec']['containers'][0]['command'] = args
with open('/etc/kubernetes/manifests/kube-controller-manager.yaml', 'w') as f:
yaml.dump(m, f, default_flow_style=False)
CM_PATCH
python3 - <<'AS_PATCH'
import yaml
with open('/etc/kubernetes/manifests/kube-apiserver.yaml') as f:
m = yaml.safe_load(f)
args = m['spec']['containers'][0]['command']
for flag in ['--default-unreachable-toleration-seconds=60', '--default-not-ready-toleration-seconds=60']:
key = flag.split('=')[0]
args = [a for a in args if not a.startswith(key)]
args.append(flag)
m['spec']['containers'][0]['command'] = args
with open('/etc/kubernetes/manifests/kube-apiserver.yaml', 'w') as f:
yaml.dump(m, f, default_flow_style=False)
AS_PATCH
fi