Files
home-network-k3s-impl/infra/ansible/roles/node_baseline/tasks/main.yml
T
jakman85andClaude Opus 4.8 af5fc5b25f feat(tofu,ansible): SSD-backed etcd disk per k3s node (Phase 1: code + plan)
Interim bridge to stop Longhorn replica-rebuild I/O storms on the shared HDD
Storage pool from starving etcd WAL fsync (crash-looping k3s / flapping the
kube-vip VIP). Adds a small dedicated SSD disk per node for etcd only; Longhorn
stays on HDD. See docs/plans/ssd-etcd-isolation.md.

tofu (infra/tofu):
- New vars etcd_ssd_datastore (default "local-zfs" = rpool/data, Micron 5100
  SATA SSD mirror w/ PLP) and etcd_disk_gib (default 16).
- New virtio2 disk block on the SSD datastore per VM: discard=on, cache=none
  (honor guest fsync straight to the ZFS ZIL — safe on PLP SSD), iothread=false.
  Kept last (ascending interface) so bpg does not reorder virtio0/virtio1.
- Revert the debian_cloud_image resource to the long type name
  proxmox_virtual_environment_download_file to match the R2 state: bpg >= 0.111
  dropped the cross-type moved{} linkage to the short proxmox_download_file, so
  the stale moved block failed EVERY plan with "Resource type mismatch" (broken
  on main too). Aligning code to state yields a clean plan with no image
  re-download. Short-name migration is deferred to a deliberate `tofu state mv`.

ansible (node_baseline):
- Format /dev/vdc (label k3s-etcd) and mount it at
  /var/lib/rancher/k3s/server/db (defaults,noatime; no nofail so a missing etcd
  disk fails loudly rather than silently landing etcd on the root HDD) before
  k3s starts, so a rebuilt node comes up with etcd isolated on SSD. Data-safe:
  filesystem module never reformats an existing fs.

Phase 1 only: non-disruptive. No tofu apply, no node/VM/etcd/Longhorn changes.
tofu plan verified: 0 to add, 3 to change, 0 to destroy — every VM an in-place
disk ADD (virtio2), dev-3 also an in-place memory 16384->24576; no VM replace.
Merge gate green (render==golden included).

Co-Authored-By: Claude Opus 4.8 <[email protected]>
2026-08-29 17:21:06 -05:00

109 lines
4.1 KiB
YAML

---
- name: Install baseline packages (guest agent, Longhorn/iscsi/nfs prereqs)
ansible.builtin.apt:
name: "{{ node_baseline_packages }}"
state: present
update_cache: true
cache_valid_time: 3600
- name: Persist kernel modules for k3s/Cilium/Longhorn
ansible.builtin.copy:
dest: /etc/modules-load.d/k3s-cilium-longhorn.conf
owner: root
group: root
mode: "0644"
content: "{{ node_baseline_kernel_modules | join('\n') }}\n"
- name: Load kernel modules now
community.general.modprobe:
name: "{{ item }}"
state: present
loop: "{{ node_baseline_kernel_modules }}"
- name: Install sysctl tuning for k3s/Cilium
ansible.builtin.copy:
dest: /etc/sysctl.d/99-k3s-cilium.conf
owner: root
group: root
mode: "0644"
content: |
net.bridge.bridge-nf-call-iptables = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward = 1
net.ipv6.conf.all.forwarding = 1
fs.inotify.max_user_instances = 8192
fs.inotify.max_user_watches = 524288
notify: Reload sysctl
- name: Enable and start iscsid (Longhorn prerequisite)
ansible.builtin.systemd:
name: iscsid
enabled: true
state: started
# qemu-guest-agent binds to the virtio-serial channel /dev/virtio-ports/org.qemu.guest_agent.0,
# which Proxmox attaches only when the VM's `agent` option is enabled. Our tofu keeps agent
# DISABLED on purpose (enabling it makes `tofu apply` block up to 15m waiting for an agent the
# stock Debian cloud image hasn't installed yet — bpg gotcha). So we ENABLE the unit for the day
# a channel exists, but only START it when the channel is actually present — never fail the
# baseline over a missing hypervisor channel.
- name: Check whether the qemu guest-agent virtio channel is attached
ansible.builtin.stat:
path: /dev/virtio-ports/org.qemu.guest_agent.0
register: node_baseline_qga_channel
- name: Enable qemu-guest-agent (start only when its virtio channel is present)
ansible.builtin.systemd:
name: qemu-guest-agent
enabled: true
state: "{{ 'started' if node_baseline_qga_channel.stat.exists else 'stopped' }}"
- name: Create ext4 filesystem on the Longhorn data disk (data-safe; skips if present)
community.general.filesystem:
fstype: ext4
dev: "{{ node_baseline_longhorn_device }}"
opts: "-L {{ node_baseline_longhorn_fs_label }}"
- name: Mount the Longhorn data disk
ansible.posix.mount:
path: "{{ node_baseline_longhorn_mount }}"
src: "LABEL={{ node_baseline_longhorn_fs_label }}"
fstype: ext4
opts: "defaults,nofail,x-systemd.device-timeout=5s"
state: mounted
# Dedicated SSD etcd disk (docs/plans/ssd-etcd-isolation.md). Formats /dev/vdc and
# mounts it at the k3s etcd data dir BEFORE k3s starts, so a rebuilt node comes up with
# etcd already isolated on SSD. Data-safe: community.general.filesystem never reformats
# a disk that already carries a filesystem, so re-running against an already-migrated
# node leaves the etcd data intact. On EXISTING nodes the one-time data migration
# (stop k3s -> rsync db -> mount) is done manually per the plan's §4.3 before this
# role would mount over a populated directory.
- name: Create ext4 filesystem on the dedicated etcd SSD disk (data-safe; skips if present)
community.general.filesystem:
fstype: ext4
dev: "{{ node_baseline_etcd_device }}"
opts: "-L {{ node_baseline_etcd_fs_label }}"
- name: Mount the dedicated etcd SSD disk at the k3s etcd data dir
ansible.posix.mount:
path: "{{ node_baseline_etcd_mount }}"
src: "LABEL={{ node_baseline_etcd_fs_label }}"
fstype: ext4
# noatime: fewer metadata writes under etcd's fsync-heavy load. No `nofail`: a
# missing etcd disk MUST fail loudly rather than let k3s start etcd on the root HDD.
opts: "defaults,noatime"
dump: "0"
passno: "2"
state: mounted
- name: Disable swap now
ansible.builtin.command: swapoff -a
changed_when: false
- name: Neutralize swap entries in fstab (kubelet requires swap off)
ansible.builtin.replace:
path: /etc/fstab
regexp: '^([^#].*\sswap\s.*)$'
replace: '# \1 # disabled for k3s/kubelet'