infra/docs/runbooks/vault-token-renew-devvm.md

Runbook: devvm Vault token auto-renewal

Host: devvm (10.0.10.10), user wizard Source of truth: infra/scripts/vault-token-renew.{sh,service,timer} Live paths: ~/.local/bin/vault-token-renew, ~/.config/systemd/user/vault-token-renew.{service,timer}

What this is

wizard@devvm authenticates to Vault with a periodic, orphan token stored in ~/.vault-token, instead of a 7-day OIDC login that needed weekly re-auth. A systemd user timer renews it daily so it never expires.

Property	Value
display_name	token-devvm-wizard
period	768h (32 days)
explicit_max_ttl	0 (no hard cap)
policies	default, sops-admin, vault-admin
orphan	true (not revoked when any parent expires)

Periodic tokens have no max-TTL; they only need renewing once per period. Daily renewal leaves a 32× margin. If devvm is decommissioned and the timer stops, the token self-expires within ~32 days — deliberately, unlike a root token which would live forever (this is the security trade-off Viktor chose: periodic + renewer over a never-expiring root token).

Deploy on a fresh devvm

The renewer is a host-side script + user systemd units, deployed manually (same model as the other infra/scripts/ host scripts). From a checkout of the repo as user wizard on devvm:

cd ~/code/infra/scripts
install -m 0755 vault-token-renew.sh ~/.local/bin/vault-token-renew   # strip .sh
install -m 0644 vault-token-renew.service vault-token-renew.timer ~/.config/systemd/user/

# user manager must survive logout, so the daily timer fires headless
loginctl enable-linger "$USER"

systemctl --user daemon-reload
systemctl --user enable --now vault-token-renew.timer

Then mint the token (one-time, interactive — see below). The script and units carry no secret; only the token itself is sensitive and stays out of git.

Mint / re-mint the token

Requires an interactive OIDC login (browser), so it can't run unattended:

export VAULT_ADDR=https://vault.viktorbarzin.me
vault login -method=oidc
vault token create -orphan -period=768h \
  -policy=vault-admin -policy=sops-admin -display-name=devvm-wizard \
  -field=token > ~/.vault-token
chmod 600 ~/.vault-token

Vault prefixes the display name, so it becomes token-devvm-wizard (which is what the drift guard checks for). -orphan is essential: a child of the 7-day OIDC token would be revoked when that parent expired.

Health check

export VAULT_ADDR=https://vault.viktorbarzin.me
vault token lookup | grep -E 'display_name|period|explicit_max_ttl|policies'
# expect: display_name token-devvm-wizard, period 768h, explicit_max_ttl 0s,
#         policies [default sops-admin vault-admin]

# authoritative write-capability check (do NOT trust the policies field alone —
# an OIDC token shows policies=[default] but carries vault-admin via identity):
vault token capabilities secret/data/viktor   # expect create/update/.../sudo

# renewer health
systemctl --user list-timers | grep vault-token-renew     # next/last run
tail -5 ~/.local/state/vault-token-renew.log              # recent results

A healthy log line looks like: <ts> OK renewed (dn=token-devvm-wizard ttl=2764800s) (ttl 2764800s = 768h).

After an OIDC login you'll instead see, at the next nightly run: <ts> HEALED: re-minted periodic token from foreign dn=oidc-… (revoked N stale periodic token(s)) — that's the self-heal working as designed.

Drift guard & self-heal

~/.vault-token is the Vault CLI's default token sink, so any vault login overwrites it. Two confirmed clobber vectors:

1. vault login -method=oidc → replaces it with a 7-day OIDC token (the renewer can't push past the OIDC role's 7-day token_max_ttl). The infra docs prescribe this login before applies, so it recurs — it went unnoticed for weeks twice (2026-06-18→26, 2026-06-29→07-03) and read as "Vault expires weekly".
2. A stray vault login -method=kubernetes (e.g. a headless agent flow) → writes a read-only kubernetes-woodpecker-default token (can read Vault but cannot write secret/*). Happened 2026-06-05, unnoticed for two days.

Since 2026-07-03 the renewer self-heals (docs/plans/2026-07-03-vault-token-self-heal-design.md). On a foreign token it attempts the re-mint with the clobbering token's own authority and lets Vault's authz decide:

• Admin-capable clobber (OIDC login) → re-mints the periodic token, sanity-checks it against the drift guard, atomically replaces ~/.vault-token, revokes stale token-devvm-wizard leftovers (anti-sprawl), logs HEALED: re-minted periodic token from foreign dn=… (revoked N stale periodic token(s)) and exits 0. The clobbering token is NOT revoked — it may still back a live login session; it ages out on its own.
• Weak clobber (read-only k8s token) → the mint is denied; logs DRIFT: … heal denied, foreign token lacks create authority …; investigate what wrote it and exits non-zero (unit failed). Deliberately loud: this signals a misbehaving agent flow — exactly the 2026-06-05 case.

Manual recovery is only needed for the weak-clobber case (the DRIFT log line still contains the exact command) — run the mint/re-mint block.

Tests

infra/scripts/test-vault-token-renew.sh unit-tests the drift-guard decision, the lookup-JSON parsers (including the exact 2026-06-05 woodpecker-clobber case), and the self-heal's revoke filter (which stale periodic tokens a heal may sweep). Run: bash infra/scripts/test-vault-token-renew.sh.