Add Arc testnet node (Circle L1): arc-execution EL + arc-consensus CL

Generated compose for the new `arc` client. Single self-contained stack:
3 init containers (snapshot download ~84GB, CL key init, socket prep) +
EL (reth-fork, http RPC behind traefik /arc-testnet, dshackle upstream
chain: arc-testnet) + CL (follows relay endpoints, drives EL over shared
IPC sockets). Images pulled anonymously from Circle's public Cloudsmith
registry at 0.7.2. Positional subcommands pinned in entrypoint so
process_yaml's command-sorting can't reorder them.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

arc/arc/arc-testnet-arc-full.yml

@@ -0,0 +1,198 @@
+---
+x-logging-defaults: &logging-defaults
+  driver: json-file
+  options:
+    max-size: "10m"
+    max-file: "3"
+
+# Usage:
+#
+# mkdir rpc && cd rpc
+#
+# git init
+# git remote add origin https://github.com/StakeSquid/ethereum-rpc-docker.git
+# git fetch origin vibe
+# git checkout origin/vibe
+#
+# docker run --rm alpine sh -c "printf '0x'; head -c32 /dev/urandom | xxd -p -c 64" > .jwtsecret
+#
+# env
+# ...
+# IP=$(curl ipinfo.io/ip)
+# DOMAIN=${IP}.traefik.me
+# COMPOSE_FILE=base.yml:rpc.yml:arc/arc/arc-testnet-arc-full.yml
+#
+# docker compose up -d
+#
+# curl -X POST https://${IP}.traefik.me/arc-testnet \
+#   -H "Content-Type: application/json" \
+#   --data '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}'
+
+services:
+  arc-testnet-snapshots:
+    image: ${ARC_ARC_IMAGE:-docker.cloudsmith.io/circle/arc-network/arc-execution}:${ARC_TESTNET_ARC_VERSION:-0.7.2}
+    user: root
+    entrypoint: [/usr/local/bin/arc-snapshots, download]
+    command:
+      - --chain=arc-testnet
+      - --consensus-path=/data/consensus
+      - --execution-path=/data/execution
+    restart: no
+    networks:
+      - chains
+    volumes:
+      - ${ARC_TESTNET_ARC_FULL_CONSENSUS_DATA:-arc-testnet-arc-full-consensus}:/data/consensus
+      - ${ARC_TESTNET_ARC_FULL_EXECUTION_DATA:-arc-testnet-arc-full-execution}:/data/execution
+    logging: *logging-defaults
+
+  arc-testnet-consensus-init:
+    image: ${ARC_CONSENSUS_IMAGE:-docker.cloudsmith.io/circle/arc-network/arc-consensus}:${ARC_TESTNET_CONSENSUS_VERSION:-0.7.2}
+    user: root
+    entrypoint: [/usr/local/bin/arc-node-consensus, init]
+    command:
+      - --home=/data/consensus
+    restart: no
+    depends_on:
+      arc-testnet-snapshots:
+        condition: service_completed_successfully
+    networks:
+      - chains
+    volumes:
+      - ${ARC_TESTNET_ARC_FULL_CONSENSUS_DATA:-arc-testnet-arc-full-consensus}:/data/consensus
+    logging: *logging-defaults
+
+  arc-testnet-sockets-init:
+    image: debian:bookworm-slim
+    entrypoint: [/bin/sh, -c]
+    command: [rm -f /sockets/*.ipc && chown 999:999 /sockets]
+    restart: no
+    depends_on:
+      arc-testnet-consensus-init:
+        condition: service_completed_successfully
+    networks:
+      - chains
+    volumes:
+      - arc-testnet-arc-full-sockets:/sockets
+    logging: *logging-defaults
+
+  arc-testnet:
+    image: ${ARC_ARC_IMAGE:-docker.cloudsmith.io/circle/arc-network/arc-execution}:${ARC_TESTNET_ARC_VERSION:-0.7.2}
+    sysctls:
+      # TCP Performance
+      net.ipv4.tcp_slow_start_after_idle: 0       # Disable slow start after idle
+      net.ipv4.tcp_no_metrics_save: 1             # Disable metrics cache
+      net.ipv4.tcp_rmem: 4096 87380 16777216      # Increase TCP read buffers
+      net.ipv4.tcp_wmem: 4096 87380 16777216      # Increase TCP write buffers
+      net.core.somaxconn: 32768                   # Higher connection queue
+      # Memory/Connection Management
+      # net.core.netdev_max_backlog: 50000          # Increase network buffer
+      net.ipv4.tcp_max_syn_backlog: 30000         # More SYN requests
+      net.ipv4.tcp_max_tw_buckets: 2000000        # Allow more TIME_WAIT sockets
+    ulimits:
+      nofile: 1048576    # Max open files (for RPC/WS connections)
+    user: root
+    expose:
+      - 8545
+      - 9001
+    entrypoint: [/usr/local/bin/arc-node-execution, node]
+    command:
+      - --auth-ipc
+      - --auth-ipc.path=/sockets/auth.ipc
+      - --chain=arc-testnet
+      - --datadir=/data/execution
+      - --disable-discovery
+      - --enable-arc-rpc
+      - --full
+      - --http
+      - --http.addr=0.0.0.0
+      - --http.api=eth,net,web3,txpool,trace,debug
+      - --http.port=8545
+      - --ipcpath=/sockets/reth.ipc
+      - --log.file.directory=/data/execution/logs
+      - --metrics=0.0.0.0:9001
+      - --rpc.forwarder=https://rpc.quicknode.testnet.arc.network/
+    restart: unless-stopped
+    stop_grace_period: 5m
+    depends_on:
+      arc-testnet-sockets-init:
+        condition: service_completed_successfully
+    networks:
+      - chains
+    volumes:
+      - ${ARC_TESTNET_ARC_FULL_EXECUTION_DATA:-arc-testnet-arc-full-execution}:/data/execution
+      - /slowdisk:/slowdisk
+      - arc-testnet-arc-full-sockets:/sockets
+    logging: *logging-defaults
+    labels:
+      - prometheus-scrape.enabled=true
+      - prometheus-scrape.port=9001
+      - prometheus-scrape.path=/metrics
+      - traefik.enable=true
+      - traefik.http.middlewares.arc-testnet-arc-full-stripprefix.stripprefix.prefixes=/arc-testnet
+      - traefik.http.services.arc-testnet-arc-full.loadbalancer.server.port=8545
+      - ${NO_SSL:-traefik.http.routers.arc-testnet-arc-full.entrypoints=websecure}
+      - ${NO_SSL:-traefik.http.routers.arc-testnet-arc-full.tls.certresolver=myresolver}
+      - ${NO_SSL:-traefik.http.routers.arc-testnet-arc-full.rule=Host(`$DOMAIN`) && (Path(`/arc-testnet`) || Path(`/arc-testnet/`))}
+      - ${NO_SSL:+traefik.http.routers.arc-testnet-arc-full.rule=Path(`/arc-testnet`) || Path(`/arc-testnet/`)}
+      - traefik.http.routers.arc-testnet-arc-full.middlewares=arc-testnet-arc-full-stripprefix, ipallowlist
+
+  arc-testnet-consensus:
+    image: ${ARC_CONSENSUS_IMAGE:-docker.cloudsmith.io/circle/arc-network/arc-consensus}:${ARC_TESTNET_CONSENSUS_VERSION:-0.7.2}
+    user: root
+    expose:
+      - 31000
+      - 29000
+    entrypoint: [/usr/local/bin/arc-node-consensus, start]
+    command:
+      - --eth-socket=/sockets/reth.ipc
+      - --execution-persistence-backpressure
+      - --execution-persistence-backpressure-threshold=50
+      - --execution-socket=/sockets/auth.ipc
+      - --follow
+      - --follow.endpoint=https://rpc.blockdaemon.testnet.arc.network,wss=rpc.blockdaemon.testnet.arc.network/websocket
+      - --follow.endpoint=https://rpc.drpc.testnet.arc.network,wss=rpc.drpc.testnet.arc.network
+      - --follow.endpoint=https://rpc.quicknode.testnet.arc.network,wss=rpc.quicknode.testnet.arc.network
+      - --full
+      - --home=/data/consensus
+      - --metrics=0.0.0.0:29000
+      - --rpc.addr=0.0.0.0:31000
+    restart: unless-stopped
+    stop_grace_period: 5m
+    depends_on:
+      arc-testnet-consensus-init:
+        condition: service_completed_successfully
+      arc-testnet:
+        condition: service_started
+    networks:
+      - chains
+    volumes:
+      - ${ARC_TESTNET_ARC_FULL_CONSENSUS_DATA:-arc-testnet-arc-full-consensus}:/data/consensus
+      - arc-testnet-arc-full-sockets:/sockets
+    logging: *logging-defaults
+    labels:
+      - prometheus-scrape.enabled=true
+      - prometheus-scrape.port=29000
+
+volumes:
+  arc-testnet-arc-full-consensus:
+  arc-testnet-arc-full-execution:
+  arc-testnet-arc-full-sockets:
+
+x-upstreams:
+  - id: $${ID}
+    labels:
+      provider: $${PROVIDER}
+    connection:
+      generic:
+        rpc:
+          url: $${RPC_URL}
+    chain: arc-testnet
+    method-groups:
+      enabled:
+        - debug
+        - filter
+        - trace
+    methods:
+      enabled:
+        - name: txpool_content
+...

compose_registry.json

@@ -791,6 +791,22 @@
       "arbitrum-sepolia-nitro-erigon-pruned-trace"
     ]
   },
+  {
+    "chain": "testnet",
+    "client": "arc",
+    "compose_file": "arc/arc/arc-testnet-arc-full",
+    "features": [],
+    "network": "arc",
+    "node": null,
+    "relay": null,
+    "stack": null,
+    "type": "full",
+    "volumes": [
+      "arc-testnet-arc-full-consensus",
+      "arc-testnet-arc-full-execution",
+      "arc-testnet-arc-full-sockets"
+    ]
+  },
   {
     "chain": "fuji",
     "client": "go",