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>
This commit is contained in:
Viktor Barzin
parent
e4c0cbc3d0
commit
8ed427a7e4
7 changed files with 408 additions and 201 deletions
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@ -10,8 +10,9 @@
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variable "proxmox_host" { type = string }
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variable "ssh_public_key" {
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type = string
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default = ""
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type = string
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default = ""
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description = "DEPRECATED: was a tfvars input. Now read from Vault secret/viktor.ssh_public_key directly (see locals.k8s_ssh_public_key) so no apply-time argument can leave the snippet's authorized_keys empty."
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}
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variable "k8s_join_command" { type = string }
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@ -40,6 +41,12 @@ locals {
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non_k8s_cloud_init_image_path = "/var/lib/vz/template/iso/noble-server-cloudimg-amd64-non-k8s.img"
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cloud_init_image_url = "https://cloud-images.ubuntu.com/noble/current/noble-server-cloudimg-amd64.img"
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# Source of truth for the wizard user's SSH key on every cloud-init
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# generated VM. Lives in Vault so we never apply with an empty value
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# (which silently locked the wizard account on the node5 v1 boot —
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# 2026-05-26). Falls back to var.ssh_public_key for backward compat.
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k8s_ssh_public_key = try(data.vault_kv_secret_v2.viktor.data["ssh_public_key"], var.ssh_public_key)
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}
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# ---------------------------------------------------------------------------
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@ -52,7 +59,7 @@ module "k8s-node-template" {
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proxmox_user = "root" # SSH user on Proxmox host
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ssh_private_key = data.vault_kv_secret_v2.secrets.data["ssh_private_key"]
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ssh_public_key = var.ssh_public_key
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ssh_public_key = local.k8s_ssh_public_key
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cloud_image_url = local.cloud_init_image_url
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image_path = local.k8s_cloud_init_image_path
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@ -62,167 +69,10 @@ module "k8s-node-template" {
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is_k8s_template = true # provision cloud init file with k8s deps
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snippet_name = local.k8s_cloud_init_snippet_name
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# Add mirror registry
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containerd_config_update_command = <<-EOF
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# Set up config_path for per-registry mirror configuration.
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# NOTE: containerd v2 writes `config_path = ''` (single quotes) on
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# `config default`; v1 writes `config_path = ""`. Match both forms so this
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# is idempotent across versions. Without the v2 match, hosts.toml mirror
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# config is silently ignored — observed 2026-05-26 on node4 (containerd v2.2.4).
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sed -i 's|config_path = .*|config_path = "/etc/containerd/certs.d"|' /etc/containerd/config.toml
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# Create hosts.toml for docker.io (Docker Hub) — high traffic, rate-limited
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mkdir -p /etc/containerd/certs.d/docker.io
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printf 'server = "https://registry-1.docker.io"\n\n[host."http://10.0.20.10:5000"]\n capabilities = ["pull", "resolve"]\n\n[host."https://registry-1.docker.io"]\n capabilities = ["pull", "resolve"]\n' > /etc/containerd/certs.d/docker.io/hosts.toml
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# Create hosts.toml for ghcr.io — medium traffic
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mkdir -p /etc/containerd/certs.d/ghcr.io
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printf 'server = "https://ghcr.io"\n\n[host."http://10.0.20.10:5010"]\n capabilities = ["pull", "resolve"]\n\n[host."https://ghcr.io"]\n capabilities = ["pull", "resolve"]\n' > /etc/containerd/certs.d/ghcr.io/hosts.toml
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# Forgejo OCI registry: redirect to in-cluster Traefik LB (10.0.20.200) so
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# pulls don't hairpin out through the WAN gateway. Traefik serves the
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# *.viktorbarzin.me wildcard so SNI verification still passes.
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# registry.viktorbarzin.me / 10.0.20.10:5050 entries removed in Phase 4 of
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# the forgejo-registry-consolidation 2026-05-07 — registry-private is gone.
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mkdir -p /etc/containerd/certs.d/forgejo.viktorbarzin.me
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printf 'server = "https://forgejo.viktorbarzin.me"\n\n[host."https://10.0.20.200"]\n capabilities = ["pull", "resolve"]\n' > /etc/containerd/certs.d/forgejo.viktorbarzin.me/hosts.toml
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# Low-traffic registries (registry.k8s.io, quay.io, reg.kyverno.io) pull directly.
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# Pull-through cache removed: caused corrupted images (truncated downloads)
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# breaking VPA certgen and Kyverno image pulls.
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sed -i 's/.*max_concurrent_downloads = 3/max_concurrent_downloads = 20/g' /etc/containerd/config.toml # Enable multiple concurrent downloads
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# Configure aggressive garbage collection to prevent disk space exhaustion (node2 incident prevention)
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# Set up containerd GC for unused images and containers
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cat >> /etc/containerd/config.toml << 'CONTAINERD_GC'
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[plugins."io.containerd.gc.v1.scheduler"]
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# Run GC every 30 minutes instead of default 1 hour
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pause_threshold = 0.02
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deletion_threshold = 0
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mutation_threshold = 100
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schedule_delay = "1800s" # 30 minutes
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[plugins."io.containerd.runtime.v2.task"]
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# More aggressive container cleanup
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exit_timeout = "5m"
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[plugins."io.containerd.metadata.v1.bolt"]
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# Compact database more frequently
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compact_threshold = 5242880 # 5MB instead of default 100MB
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CONTAINERD_GC
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sudo sed -i '/serializeImagePulls:/d' /var/lib/kubelet/config.yaml && \
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sudo sed -i '/maxParallelImagePulls:/d' /var/lib/kubelet/config.yaml && \
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echo -e 'serializeImagePulls: false\nmaxParallelImagePulls: 50' | sudo tee -a /var/lib/kubelet/config.yaml
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# Memory and disk reservation and eviction — prevent node OOM/disk full
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# Aggressive disk eviction settings added after node2 containerd corruption incident (2026-03-13)
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# These settings prevent disk space exhaustion that can corrupt containerd image store
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sudo sed -i '/systemReserved:/d; /kubeReserved:/d; /evictionHard:/,/^[^ ]/{ /evictionHard:/d; /^ /d }; /evictionSoft:/,/^[^ ]/{ /evictionSoft:/d; /^ /d }; /evictionSoftGracePeriod:/,/^[^ ]/{ /evictionSoftGracePeriod:/d; /^ /d }' /var/lib/kubelet/config.yaml
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cat <<'KUBELET_PATCH' | sudo tee -a /var/lib/kubelet/config.yaml
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systemReserved:
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memory: "512Mi"
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cpu: "200m"
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kubeReserved:
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memory: "512Mi"
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cpu: "200m"
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evictionHard:
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memory.available: "500Mi"
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nodefs.available: "15%" # More aggressive: evict at 15% free (was 10%)
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imagefs.available: "20%" # Much more aggressive: evict at 20% free to prevent containerd corruption
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evictionSoft:
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memory.available: "1Gi"
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nodefs.available: "20%" # Start warnings at 20% free
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imagefs.available: "25%" # Start warnings at 25% free for containerd safety
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evictionSoftGracePeriod:
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memory.available: "30s"
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nodefs.available: "60s" # Grace period for disk space warnings
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imagefs.available: "30s" # Shorter grace for critical containerd space
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memorySwap:
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swapBehavior: "LimitedSwap"
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KUBELET_PATCH
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# Remove old 2-bucket shutdown config if present (replaced by priority-based)
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sudo sed -i '/^shutdownGracePeriod:/d; /^shutdownGracePeriodCriticalPods:/d' /var/lib/kubelet/config.yaml
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# Remove old shutdownGracePeriodByPodPriority block if present (idempotent re-apply)
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sudo python3 -c "
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import yaml, sys
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with open('/var/lib/kubelet/config.yaml') as f:
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cfg = yaml.safe_load(f)
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cfg.pop('shutdownGracePeriod', None)
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cfg.pop('shutdownGracePeriodCriticalPods', None)
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cfg.pop('shutdownGracePeriodByPodPriority', None)
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# Container log rotation limits — reduces root disk writes (~20-30 GB/day savings)
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cfg['containerLogMaxSize'] = '10Mi'
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cfg['containerLogMaxFiles'] = 3
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cfg['shutdownGracePeriodByPodPriority'] = [
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{'priority': 0, 'shutdownGracePeriodSeconds': 20},
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{'priority': 200000, 'shutdownGracePeriodSeconds': 20},
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{'priority': 400000, 'shutdownGracePeriodSeconds': 30},
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{'priority': 600000, 'shutdownGracePeriodSeconds': 30},
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{'priority': 800000, 'shutdownGracePeriodSeconds': 90},
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{'priority': 1000000, 'shutdownGracePeriodSeconds': 30},
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{'priority': 1200000, 'shutdownGracePeriodSeconds': 30},
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{'priority': 2000000000, 'shutdownGracePeriodSeconds': 30},
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{'priority': 2000001000, 'shutdownGracePeriodSeconds': 30},
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]
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with open('/var/lib/kubelet/config.yaml', 'w') as f:
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yaml.dump(cfg, f, default_flow_style=False)
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"
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# Systemd: increase InhibitDelayMaxSec so logind doesn't force-kill before kubelet finishes graceful shutdown
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# Total kubelet shutdown time: 310s. InhibitDelay must exceed this.
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mkdir -p /etc/systemd/logind.conf.d
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cat <<'LOGIND_CONF' | sudo tee /etc/systemd/logind.conf.d/kubelet-shutdown.conf
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[Login]
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InhibitDelayMaxSec=480
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LOGIND_CONF
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sudo systemctl restart systemd-logind
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# Systemd: increase kubelet stop timeout to match total shutdown grace period (310s + buffer)
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mkdir -p /etc/systemd/system/kubelet.service.d
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cat <<'KUBELET_SHUTDOWN' | sudo tee /etc/systemd/system/kubelet.service.d/20-shutdown.conf
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[Service]
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TimeoutStopSec=420s
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KUBELET_SHUTDOWN
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sudo systemctl daemon-reload
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# Tune controller-manager + apiserver for faster volume detach on node failure
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# Only on master node (has static pod manifests)
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if [ -f /etc/kubernetes/manifests/kube-controller-manager.yaml ]; then
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sudo python3 -c "
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import yaml
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# Controller-manager: faster attach-detach reconciliation (15s vs 1m default)
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with open('/etc/kubernetes/manifests/kube-controller-manager.yaml') as f:
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m = yaml.safe_load(f)
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args = m['spec']['containers'][0]['command']
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for flag in ['--attach-detach-reconcile-sync-period=15s']:
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key = flag.split('=')[0]
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args = [a for a in args if not a.startswith(key)]
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args.append(flag)
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m['spec']['containers'][0]['command'] = args
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with open('/etc/kubernetes/manifests/kube-controller-manager.yaml', 'w') as f:
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yaml.dump(m, f, default_flow_style=False)
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print('controller-manager: attach-detach-reconcile-sync-period=15s')
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"
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sudo python3 -c "
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import yaml
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# API server: faster pod eviction from unreachable nodes (60s vs 300s default)
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with open('/etc/kubernetes/manifests/kube-apiserver.yaml') as f:
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m = yaml.safe_load(f)
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args = m['spec']['containers'][0]['command']
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for flag in ['--default-unreachable-toleration-seconds=60', '--default-not-ready-toleration-seconds=60']:
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key = flag.split('=')[0]
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args = [a for a in args if not a.startswith(key)]
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args.append(flag)
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m['spec']['containers'][0]['command'] = args
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with open('/etc/kubernetes/manifests/kube-apiserver.yaml', 'w') as f:
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yaml.dump(m, f, default_flow_style=False)
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print('apiserver: unreachable+not-ready toleration=60s')
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"
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fi
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EOF
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# containerd setup script now bundled in the module
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# (k8s-node-containerd-setup.sh); the deprecated variable is
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# ignored when is_k8s_template=true.
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containerd_config_update_command = ""
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k8s_join_command = var.k8s_join_command
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}
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@ -107,6 +107,8 @@ locals {
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"k8s-node2" = { vmid = 202, proxmox_node = "pve" }
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"k8s-node3" = { vmid = 203, proxmox_node = "pve" }
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"k8s-node4" = { vmid = 204, proxmox_node = "pve" }
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"k8s-node5" = { vmid = 205, proxmox_node = "pve" }
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"k8s-node6" = { vmid = 206, proxmox_node = "pve" }
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}
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}
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