Memcached

Description

This Ansible role runs Memcached as a central engine dependency, mirroring the central-database pattern (svc-db-postgres). A consumer reaches it either embedded (a sidecar inside its own stack, shared: false) or from this central pinned stack (shared: true).

Overview

Built as one of the central engine roles described in docs/architecture/central-engines.md, this role:

Deploys a standalone Memcached stack pinned to the swarm manager (placement: manager).
Waits until the container is running and the engine answers the version handshake.
Ships an embedded sidecar snippet (templates/service.yml.j2) for the shared: false opt-out path.

Cosmos

The diagram places Memcached in the Infinito.Nexus cosmos: the components it deploys (capabilities), the central services it consumes (dependencies), and its outward reach (federation and bridged external networks).

flowchart LR
    subgraph deps [Dependencies]
        dep_svc_net_tor["svc-net-tor 🐳🐝"]
    end
    subgraph role [svc-db-memcached 🐳🐝]
        svc_memcached["memcached"]
        svc_tor["tor"]
    end
    subgraph dependents [Dependents]
        dpt_web_app_zammad["web-app-zammad 🐳🐝"]
    end
    dep_svc_net_tor -. "0..1" .-> svc_tor
    svc_memcached -. "0..1" .-> dpt_web_app_zammad

Solid 1:1 edges are fixed relationships; dashed 0..1 edges are conditional (enabled only in matching deployments); red 0..0 edges are turned off in this role. Node markers show the role's deploy modes (💻 host, 🐳 compose, 🐝 swarm); ❌ marks a service that is explicitly turned off, and ⚙️ an Ansible role dependency declared in meta/main.yml.

Per-consumer isolation

Memcached has no native auth or namespace. Consumer isolation is key-prefix only and is resolved by lookup('engine', 'memcached', consumer_id) at consume time, so tasks/01_init.yml is a no-op.

Features

Automated provisioning: Configured by Ansible without manual steps.
Central or embedded: Same shared toggle as the central databases.
Readiness gating: Bootstrap blocks until the engine accepts connections.

Quick Setup

Development

Clone, set up the workstation, and deploy Memcached onto the local stack:

git clone https://github.com/infinito-nexus/core.git
cd core
make onboard
make compose-deploy mode=reinstall apps=svc-db-memcached full_cycle=false

Production

Run the published image to provision the inventory and deploy Memcached to a managed server (the mounted volume persists the inventory):

APP=svc-db-memcached
HOST=<your-server>
DOMAIN=<your-domain>
TLS_MODE=self_signed
SSH_PUBLIC_KEY="<your-ssh-public-key>"

docker run --rm -it \
  -v "$PWD/inventories:/etc/infinito.nexus/inventories" \
  -e APP="$APP" -e HOST="$HOST" -e DOMAIN="$DOMAIN" -e TLS_MODE="$TLS_MODE" -e SSH_PUBLIC_KEY="$SSH_PUBLIC_KEY" \
  ghcr.io/infinito-nexus/core/debian bash -c '
    INVENTORY=/etc/infinito.nexus/inventories/production
    infinito administration inventory provision "$INVENTORY" \
      --inventory-file "$INVENTORY/devices.yml" \
      --host "$HOST" \
      --include "$APP" \
      --vars "{\"TLS_MODE\": \"$TLS_MODE\", \"DOMAIN_PRIMARY\": \"$DOMAIN\", \"users\": {\"administrator\": {\"authorized_keys\": [\"$SSH_PUBLIC_KEY\"]}}}" &&
    infinito administration deploy dedicated "$INVENTORY/devices.yml" \
      --password-file "$INVENTORY/.password" \
      --diff -vv'

Further Resources

Credits

Implemented by Kevin Veen-Birkenbach. Part of the Infinito.Nexus Project and maintained by Kevin Veen-Birkenbach. Licensed under the Infinito.Nexus Community License (Non-Commercial).