feat(fleet): give the media servers an I/O share that actually exists #110
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@@ -0,0 +1,14 @@
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# The io controller is what makes IOWeight= mean anything, and systemd does not
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# enable it below `user.slice` by default: with io accounting off, `io` never
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# appears in `user.slice/cgroup.subtree_control`, so no rootless container can
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# have an `io.weight` file and `IOWeight=` in a quadlet is silently inert.
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# Measured on Dankserver 2026-10-31: setting this property flipped
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# `user.slice/cgroup.subtree_control` from `cpu memory pids` to `cpu io memory
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# pids` immediately, with nothing restarted.
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#
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# This is half the fix; the other half is delegating io to user@1000.service
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# (user@1000.service.d/io-delegate.conf). Both must be in place before a reboot,
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# because the delegation is read when the user manager starts. Law and the
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# verification command: [[Quadlet Lifecycle]].
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[Slice]
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IOAccounting=yes
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@@ -0,0 +1,12 @@
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# The system manager gives the user manager cpu/memory/pids by default (systemd
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# 259: `systemctl show user@1000.service -p DelegateControllers` → `cpu memory
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# pids`). Without `io` in that set no `io.weight` file can exist anywhere below
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# `user.slice`, so `IOWeight=` in a rootless quadlet is silently inert — the same
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# class of trap as `RequiresMountsFor=`. Granting the controller here is what
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# makes the media servers' I/O share real.
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#
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# Inert until `user@1000.service` starts again, i.e. the next reboot (restarting
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# it would kill every rootless container on the host). Verify after the reboot
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# with the check in [[Quadlet Lifecycle]].
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[Service]
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DelegateControllers=cpu memory pids io
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@@ -61,5 +61,13 @@ ExecStartPre=/home/dank/serverAppConfigs/scripts/wait-for-mount.sh /var/lib/medi
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Restart=always
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RestartSec=5
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# A library scan reads the array for minutes on end. Weighted LOW (default is
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# 100) so that when the array is contended a scan loses to playback and to every
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# other container this user runs. Proportional share, not a cap: it changes
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# nothing while the disk is idle. 10 is a convention — the requirement is only
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# that it sit far below 100 — and it is inert until user@1000.service is
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# delegated the io controller ([[Quadlet Lifecycle]]).
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IOWeight=10
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[Install]
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WantedBy=default.target
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@@ -26,5 +26,11 @@ ExecStartPre=/home/dank/serverAppConfigs/scripts/wait-for-mount.sh /var/lib/medi
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Restart=always
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RestartSec=5
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# See the jellyfin unit for the reasoning: a section scan gets a LOW weight
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# (default 100) so a walk of 50k files loses the array to playback and to every
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# other container under this user. Inert until user@1000.service holds the io
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# controller ([[Quadlet Lifecycle]]).
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IOWeight=10
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[Install]
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WantedBy=default.target
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@@ -1208,14 +1208,47 @@ ensure_media_view() {
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# array below stays read-only and every sidecar Jellyfin writes lands on the
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# NVMe.
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# Raise it BEFORE either container starts — a start against a bare view
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# directory would let a scan clear the library database. The units also carry
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# ConditionPathIsMountPoint, so a missing view skips the start rather than
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# damaging anything. A relayout must be followed by `media-view.sh reap`
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# directory would let a scan clear the library database. Each unit gates on
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# scripts/wait-for-mount.sh, which waits and then refuses the start. A
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# relayout must be followed by `media-view.sh reap`
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# (see the Media Relayout page), which this is not.
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run_privileged bash scripts/media-view.sh install
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bash scripts/media-view.sh verify
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}
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ensure_user_io_delegate() {
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# The media servers ask for an I/O share (IOWeight= in their quadlets) so a
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# library scan cannot starve playback or the array's other reader. Two system
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# drop-ins are what make that request real, and both are host state, so the
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# deployer places them:
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# user.slice.d/io-accounting.conf io enters user.slice's subtree
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# user@1000.service.d/io-delegate.conf the user manager gets the controller
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# Without the first, `io` never appears in user.slice/cgroup.subtree_control,
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# so no container under it can have an io.weight file at all; without the
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# second the user manager never asks for the controller. systemd hands
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# user@.service cpu/memory/pids by default and drops a line it cannot honour
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# without a word — IOWeight= on its own is inert config.
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local src dst
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for src in \
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dankserver/host/systemd/user.slice.d/io-accounting.conf \
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dankserver/host/systemd/user@1000.service.d/io-delegate.conf; do
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dst=/etc/systemd/system/${src#dankserver/host/systemd/}
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run_privileged mkdir -p "$(dirname "$dst")"
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if ! run_privileged cmp -s "$src" "$dst"; then
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run_privileged install -m 644 "$src" "$dst"
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run_privileged systemctl daemon-reload
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fi
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done
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# Accounting lands immediately; the delegation is read when user@1000.service
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# starts, and restarting that unit would kill every rootless container on this
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# host. So the share becomes real at the next reboot — say so out loud rather
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# than let a quadlet line read as live config.
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if ! systemctl show user@1000.service -p DelegateControllers | grep -qw io; then
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echo "NOTE: io is not delegated to user@1000.service yet - IOWeight= is"
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echo "NOTE: inert until the next reboot (see [[Quadlet Lifecycle]])"
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fi
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}
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ensure_provider_keys() {
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# Jellyfin's metadata-provider keys live in the container-owned plugin
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# configuration under the data root, never in git; scripts/jellyfin-providers.sh
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@@ -1237,6 +1270,7 @@ ensure_provider_keys() {
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deploy_jellyfin() {
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ensure_media_view
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ensure_user_io_delegate
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ensure_provider_keys
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cp "dankserver/jellyfin/quadlet/jellyfin.container" "$quadlet_unit_dir/"
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systemctl --user daemon-reload
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@@ -1326,6 +1360,7 @@ deploy_copyparty() {
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deploy_plex() {
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ensure_media_view
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ensure_user_io_delegate
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cp "dankserver/plex/quadlet/plex.container" "$quadlet_unit_dir/"
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systemctl --user daemon-reload
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if ! systemctl --user is-active -q plex.service; then
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@@ -100,3 +100,12 @@ aborts with `DEPLOY INCOMPLETE: e2e gate FAILED` when it does not pass
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hand-off list (`HANDOFFS`) instead of a single host. The guard contract is
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untouched: challenge cleared, no authentik `uidField`, status < 500, and every
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host NOT in the list still has to land on its own vhost.
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7. **The runner's resolver is part of the suite.** A 2026-10-31 deploy of one
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Dankserver quadlet failed the gate with 21 reds spread over SSO, homepage RBAC
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and every vhost crawl — precisely the specs that navigate to an absolute
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`*.franksdank.cloud` name, while every spec on the relative `baseURL` stayed
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green. The error was `net::ERR_NAME_NOT_RESOLVED`: the workstation had lost its
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wired link, and on the fallback its resolver was no longer pinned to Pi-hole.
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Nothing on the fleet was wrong — the same suite re-run minutes later passed
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37/37. Before a mass red gets blamed on the guard chain, run
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`resolvectl query grafana.franksdank.cloud` on the box that runs the gate.
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@@ -167,6 +167,43 @@ Gate: `tests/quadlet_image_pins.bats`. Where upstream publishes no version
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tags (copyparty-ac stops at 1.19.15), pin `:latest@sha256:` and name the
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version the config label carries in the comment beside it.
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## 4b. Resource control needs host permission (measured 2026-10-31, Dankserver)
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`IOWeight=` in a rootless quadlet does nothing on its own, and nothing says so.
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The system manager delegates `cpu memory pids` to `user@.service` and **not** `io`;
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systemd drops a resource line it cannot honour **without a word** — the generator
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still emits `IOWeight=10`, the container still starts and answers its health check,
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and the cgroup simply has no `io.weight` file. Same family as
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`RequiresMountsFor=` (inert in the user manager) and `ConditionPathIsMountPoint=`
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(fail-dead): the line is accepted, the unit is happy, the setting is dead.
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Two system drop-ins make it real, both placed by `ensure_user_io_delegate` in
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`scripts/deploy-remote.sh` (repo copies under `dankserver/host/systemd/`):
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| File | Effect |
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|---|---|
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| `user.slice.d/io-accounting.conf` → `[Slice] IOAccounting=yes` | puts `io` into `user.slice/cgroup.subtree_control`; lands immediately, no restart |
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| `user@1000.service.d/io-delegate.conf` → `[Service] DelegateControllers=cpu memory pids io` | the user manager can only request controllers it was delegated; read when it starts, so it lands on **the next reboot** (restarting it kills every rootless container on the host) |
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Read the chain in this order — each line is the failure mode of the one after it:
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```bash
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cat /sys/fs/cgroup/user.slice/cgroup.subtree_control # wants: io
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systemctl show user@1000.service -p DelegateControllers # wants: io
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cat /sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/\<unit\>.service/libpod-payload-*/io.weight
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```
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`io` missing from the first → the accounting drop-in is absent. Missing from the
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second → the host has not rebooted since the delegation landed (the deployer prints
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`NOTE: io is not delegated …` for exactly this). No file at the third → that unit
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carries no weight.
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Two limits that survive the fix: a container's weight covers **everything** in its
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cgroup, so a library scan and a playback stream share one weight; and the comparison
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is made *inside* `user.slice`, so a rootless unit's weight cannot push it below a
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root unit (`frank-archon`). Shaping that pairing is the weight of `user.slice`
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itself — a fleet decision, not a unit line.
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## 5. Rootless Quadlet log retrieval
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Step 0 — establish ownership: `systemctl --user status <name>.service`
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@@ -77,7 +77,7 @@ Both prerequisites survive the dnsmasq → Pi-hole swap. Do not remove them.
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| Port 53 `bind: permission denied` crash loop after a reboot | sysctl conflict: the value must be 53 at boot, and remember `/etc/sysctl.conf` is applied **after** all of `sysctl.d/`. Redeploy pihole — `deploy_pihole` reinstalls the drop-in, neutralizes conflicting drop-ins, and comments out a stale `/etc/sysctl.conf` line |
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| Single-label name (for example `dankclaw`) answers `127.0.1.1` | The rootless container `/etc/hosts` carries the host entry (`127.0.1.1 <host>`), and FTL serves it. Use the FQDN, or add an `/etc/hosts` entry on the client |
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| Every `franksdank.cloud` name is NXDOMAIN for LAN clients while external names still answer | FTL holds no local records: `getent hosts <name>` on Dankclaw comes back empty → `podman exec pihole pihole restartdns reload` (the 2026-10-19 pitfall under **Records**) |
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| One client gets nothing while every other client is fine | FTL rate-limiting that client: `podman exec pihole grep Rate-limiting /var/log/pihole/FTL.log`. A `10.0.2.x` client address is a pasta container's DNS forwarder, not a machine |
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| One client gets nothing while every other client is fine | FTL rate-limiting that client: `podman exec pihole grep Rate-limiting /var/log/pihole/FTL.log`. A `10.0.2.x` client address is a pasta container's DNS forwarder, not a machine — and **every** rootless container on that host shares the one address, so a single chatty container throttles DNS for all of them (measured 2026-10-31: 8 throttle events in a day, all `10.0.2.100`) |
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## See Also
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@@ -106,3 +106,24 @@ load helpers
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# env file, not an Environment= line.
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! grep -qE '^Environment=CUSTOM_(USER|PASSWORD)=' "$unit" || return 1
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}
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@test "a quadlet that asks for an I/O share ships the host permission that makes it real" {
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# IOWeight= is silently inert unless the system manager both enables io for
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# user.slice and delegates it to the user manager: systemd drops a resource
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# line it cannot honour without a word and the container still starts healthy.
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# So an in-repo weight is only honest together with both drop-ins AND with a
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# deployer that places them. Measured 2026-10-31; verification chain in
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# Architecture/Quadlet Lifecycle 4b.
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if grep -lq '^IOWeight=' "$REPO_ROOT"/dankserver/*/quadlet/*.container; then
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asked=1
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else
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skip "no dankserver quadlet asks for an I/O share"
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fi
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grep -q '^IOAccounting=yes$' \
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"$REPO_ROOT/dankserver/host/systemd/user.slice.d/io-accounting.conf" || return 1
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grep -q '^DelegateControllers=.* io' \
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"$REPO_ROOT/dankserver/host/systemd/user@1000.service.d/io-delegate.conf" || return 1
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for f in user.slice.d/io-accounting.conf 'user@1000.service.d/io-delegate.conf'; do
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grep -q "dankserver/host/systemd/$f" "$REPO_ROOT/scripts/deploy-remote.sh" || return 1
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done
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}
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