Elixir Gastown Ops

Gastown Ops

Fleet Topology

• BEAM cookie: GASTOWNBEAM2026
• Node naming: egt@<hostname> — sname on all nodes
• Coordinator Phoenix port: 4000 (i9 only, PHX_SERVER=true)
• Workers: PHX_SERVER=false, GASTOWN_ROLE=polecat_worker
• Repo: http://<coordinator-ip>:3001/<user>/elixir-gastown.git

Check Cluster

# Node count from i9
ansible -i ansible/inventory i9-zfs-pop -m shell \
  -a '/opt/gastown/_build/prod/rel/elixir_gastown/bin/elixir_gastown rpc "Node.list() |> inspect() |> IO.puts"'

# From a Pi worker (avoids i9 sname/name issues)
ansible -i ansible/inventory ubrpi407 -m shell \
  -a '/opt/gastown/_build/prod/rel/elixir_gastown/bin/elixir_gastown rpc "Node.list() |> inspect() |> IO.puts"'

Expected: 10 nodes (3 coordinators + 7 Pi workers, excluding self).

Build + Deploy

Full rebuild on ubrpi502 + distribute to all Pis:

ansible-playbook -i ansible/inventory ansible/22-gastown-pis.yml -v

Distribute only (skip build):

ansible-playbook -i ansible/inventory ansible/22-gastown-pis.yml \
  --limit ubrpi401,ubrpi407,... -v
# Note: no --skip-tags build — Play 1 targets ubrpi502 only; --limit to pis skips it

Rebuild coordinator on i9:

ansible -i ansible/inventory i9-zfs-pop -m shell -a '
  cd /opt/gastown && sudo -u $DEPLOY_USER git pull origin main
  # If local changes block pull:
  sudo -u $DEPLOY_USER git stash && sudo -u $DEPLOY_USER git pull origin main
  sudo -u $DEPLOY_USER bash -c "export HOME=/home/$DEPLOY_USER MIX_ENV=prod PATH=/usr/local/bin:/usr/bin:/bin; mix release --overwrite 2>&1 | tail -5"
  systemctl restart gastown
' -b

Rustler NIF missing from coordinator release:

# Build NIF manually, then rebuild release
ansible -i ansible/inventory i9-zfs-pop -m shell -a '
  cd /opt/gastown/native/gastown_nif
  sudo -u $DEPLOY_USER bash -c "PATH=/usr/local/bin:/usr/bin:/bin cargo build --release"
  NIF=target/release/libgastown_nif.so
  DEST=/opt/gastown/_build/prod/rel/elixir_gastown/lib/elixir_gastown-0.3.0/priv/native/gastown_nif.so
  mkdir -p $(dirname $DEST) && cp $NIF $DEST && chown $DEPLOY_USER:$DEPLOY_USER $DEST
' -b
# Then re-run mix release --overwrite and restart

Common Fixes

sname/name mismatch (i9 not federating)

i9 /etc/gastown.env must have RELEASE_DISTRIBUTION=sname — not name. All nodes use sname. Check:

ansible -i ansible/inventory i9-zfs-pop,pis -m shell \
  -a 'grep RELEASE_DISTRIBUTION /etc/gastown.env /etc/gastown-worker.env 2>/dev/null'

seccomp SIGSYS on coordinator (syscall 92 = chown)

ERTS dirty I/O scheduler calls chown — blocked by SystemCallFilter=~@privileged:

ansible -i ansible/inventory i9-zfs-pop -m shell -a '
  sed -i "/SystemCallFilter=~@privileged/a SystemCallFilter=chown fchown lchown fchownat" \
    /etc/systemd/system/gastown.service
  systemctl daemon-reload && systemctl restart gastown
' -b

Verify with: journalctl -k | grep "syscall=92" — should stop after fix.

:global sync storm (nodes ejecting each other)

Symptom: nodes connect then immediately disconnect, "overlapping partitions" in logs. Cause: old binary with :global.register_name in check_singleton!. Fix: distribute new tarball (commit da9fca2+), restart workers with 15s stagger:

for h in <worker-ip-1> <worker-ip-2> <worker-ip-3>; do
  ssh ubuntu@$h "sudo systemctl restart gastown-worker"; sleep 15
done

RELEASE_NODE wrong format

Must be short name only — no @host suffix:

RELEASE_NODE=egt          ✅
RELEASE_NODE=egt@ubrpi407 ❌  (invalid for sname)

ubrpi501 chown failure in playbook

gastown_user must be {{ ansible_user }}, not hardcoded ubuntu. ubrpi501 uses ansible_user=string.

Worker not joining cluster (node not in Node.list)

1. Check /etc/gastown-worker.env — RELEASE_NODE=egt, RELEASE_DISTRIBUTION=sname
2. Check bidirectional /etc/hosts — Pi must resolve coordinator hostname AND coordinator must resolve Pi hostname
3. Add missing entry: ansible -i inventory i9-zfs-pop,pop4090,i7-zfs-pop -b -m lineinfile -a 'path=/etc/hosts regexp=".*\s<hostname>$" line="<ip> <hostname>" state=present'
4. Restart worker: sudo systemctl restart gastown-worker

Rate Limiter

HTTP endpoint on i9: GET http://<i9-ip>:4000/api/llm-permit → {"ok":true,"wait_ms":N} Release endpoint: POST http://<i9-ip>:4000/api/llm-release Zeroclaw config on Pis: /etc/gastown-worker.env → irclaw config.toml has pre_request_url. Deploy irclaw rate limit config: ansible-playbook -i inventory ansible/23-irclaw-rate-limit.yml

Key Playbooks

Hostnames vs Node Names

Pi hostnames drop leading zeros: ubrpi401 → hostname ubrpi41, node :egt@ubrpi41. Exception: ubrpi410, ubrpi411, ubrpi501, ubrpi502 keep full name.