feat: make max-outbound-peers configurable via MAX_OUTBOUND_PEERS env var

The --max-outbound-peers flag in execution-entrypoint was hardcoded to 100
with no way to override it without modifying the entrypoint directly.

Operators experiencing persistent "Send Queue full" gossipsub warnings
(#1063) need to increase this value, but had no documented way to do so.

- Add MAX_OUTBOUND_PEERS to execution-entrypoint (default: 100,
  preserving existing behaviour)
- Document the variable in .env.mainnet and .env.sepolia under a new
  PEER LIMITS section with a reference to #1063

Closes #1063 (partially)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: erhnysr

.env.mainnet

@@ -48,6 +48,12 @@ STATSD_ADDRESS="172.17.0.1"
 # FLASHBLOCKS (OPTIONAL - UNCOMMENT TO ENABLE)
 # RETH_FB_WEBSOCKET_URL=wss://mainnet.flashblocks.base.org/ws
 
+# PEER LIMITS (OPTIONAL - UNCOMMENT TO OVERRIDE DEFAULTS)
+# --------------------------------------------------------
+# Increase MAX_OUTBOUND_PEERS if you see persistent "Send Queue full" warnings.
+# See: https://github.com/base/node/issues/1063
+# MAX_OUTBOUND_PEERS=100
+
 # PRUNING (OPTIONAL - UNCOMMENT TO ENABLE)
 # NOTE: Set to any number of blocks you want, but it should be >10064
 # NOTE: The node type that was chosen when first running a node cannot be changed after the initial sync. Turning Archive into Pruned, or Pruned into Full is not supported [source](https://reth.rs/run/faq/pruning/).

.env.sepolia

@@ -48,6 +48,12 @@ STATSD_ADDRESS="172.17.0.1"
 # FLASHBLOCKS (OPTIONAL - UNCOMMENT TO ENABLE)
 # RETH_FB_WEBSOCKET_URL=wss://sepolia.flashblocks.base.org/ws
 
+# PEER LIMITS (OPTIONAL - UNCOMMENT TO OVERRIDE DEFAULTS)
+# --------------------------------------------------------
+# Increase MAX_OUTBOUND_PEERS if you see persistent "Send Queue full" warnings.
+# See: https://github.com/base/node/issues/1063
+# MAX_OUTBOUND_PEERS=100
+
 # PRUNING (OPTIONAL - UNCOMMENT TO ENABLE)
 # NOTE: Set to any number of blocks you want, but it should be >10064
 # NOTE: The node type that was chosen when first running a node cannot be changed after the initial sync. Turning Archive into Pruned, or Pruned into Full is not supported [source](https://reth.rs/run/faq/pruning/).

execution-entrypoint

@@ -10,6 +10,7 @@ METRICS_PORT="${METRICS_PORT:-6060}"
 DISCOVERY_PORT="${DISCOVERY_PORT:-30303}"
 V5_DISCOVERY_PORT="${V5_DISCOVERY_PORT:-9200}"
 P2P_PORT="${P2P_PORT:-30303}"
+MAX_OUTBOUND_PEERS="${MAX_OUTBOUND_PEERS:-100}"
 ADDITIONAL_ARGS=""
 BINARY="./base-reth-node"
 RETH_HISTORICAL_PROOFS="${RETH_HISTORICAL_PROOFS:-false}"
@@ -150,7 +151,7 @@ exec "$BINARY" node \
   --authrpc.port="$AUTHRPC_PORT" \
   --authrpc.jwtsecret="$BASE_NODE_L2_ENGINE_AUTH" \
   --metrics=0.0.0.0:"$METRICS_PORT" \
-  --max-outbound-peers=100 \
+  --max-outbound-peers="$MAX_OUTBOUND_PEERS" \
   --chain "$RETH_CHAIN" \
   --rollup.sequencer-http="$RETH_SEQUENCER_HTTP" \
   --rollup.disable-tx-pool-gossip \