fix(containerd): prevent silent network failures from leaving containers unreachable#202
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sheepbox8646 merged 3 commits intomainfrom Mar 7, 2026
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…ers unreachable Container network setup failures were silently swallowed at multiple points in the call chain, leaving containers in a "running but unreachable" ghost state. This patch closes every silent-failure path: - setupCNINetwork: return error when CNI yields no usable IP - Manager.Start: roll back container when IP is empty instead of returning success - ensureContainerAndTask: extract setupNetworkOrFail with 1 retry, propagate error to callers - ReconcileContainers: stop reporting "healthy" when network setup fails - recoverContainerIP: retry up to 2 times with backoff for transient CNI failures (IPAM lock contention, etc.) - gRPC Pool: evict connections stuck in Connecting state for >30s
After a Docker container restart, the cni0 bridge interface can linger with a zeroed MAC (00:00:00:00:00:00) and DOWN state. The CNI bridge plugin then fails with "could not set bridge's mac: invalid argument", making all MCP containers unreachable. Two-layer fix: - Entrypoint: delete cni0 and flush IPAM state before starting containerd - Go: detect bridge MAC errors in setupCNINetwork and auto-delete cni0 before retrying, as defense-in-depth for runtime recovery
sheepbox8646
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…ers unreachable (#202) * fix(containerd): prevent silent network failures from leaving containers unreachable Container network setup failures were silently swallowed at multiple points in the call chain, leaving containers in a "running but unreachable" ghost state. This patch closes every silent-failure path: - setupCNINetwork: return error when CNI yields no usable IP - Manager.Start: roll back container when IP is empty instead of returning success - ensureContainerAndTask: extract setupNetworkOrFail with 1 retry, propagate error to callers - ReconcileContainers: stop reporting "healthy" when network setup fails - recoverContainerIP: retry up to 2 times with backoff for transient CNI failures (IPAM lock contention, etc.) - gRPC Pool: evict connections stuck in Connecting state for >30s * fix(containerd): clean stale cni0 bridge on startup to prevent MAC error After a Docker container restart, the cni0 bridge interface can linger with a zeroed MAC (00:00:00:00:00:00) and DOWN state. The CNI bridge plugin then fails with "could not set bridge's mac: invalid argument", making all MCP containers unreachable. Two-layer fix: - Entrypoint: delete cni0 and flush IPAM state before starting containerd - Go: detect bridge MAC errors in setupCNINetwork and auto-delete cni0 before retrying, as defense-in-depth for runtime recovery * fix(containerd): use exec.CommandContext to satisfy noctx linter
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sheepbox8646
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* fix(containerd): prevent silent network failures from leaving containers unreachable (#202) * fix(containerd): prevent silent network failures from leaving containers unreachable Container network setup failures were silently swallowed at multiple points in the call chain, leaving containers in a "running but unreachable" ghost state. This patch closes every silent-failure path: - setupCNINetwork: return error when CNI yields no usable IP - Manager.Start: roll back container when IP is empty instead of returning success - ensureContainerAndTask: extract setupNetworkOrFail with 1 retry, propagate error to callers - ReconcileContainers: stop reporting "healthy" when network setup fails - recoverContainerIP: retry up to 2 times with backoff for transient CNI failures (IPAM lock contention, etc.) - gRPC Pool: evict connections stuck in Connecting state for >30s * fix(containerd): clean stale cni0 bridge on startup to prevent MAC error After a Docker container restart, the cni0 bridge interface can linger with a zeroed MAC (00:00:00:00:00:00) and DOWN state. The CNI bridge plugin then fails with "could not set bridge's mac: invalid argument", making all MCP containers unreachable. Two-layer fix: - Entrypoint: delete cni0 and flush IPAM state before starting containerd - Go: detect bridge MAC errors in setupCNINetwork and auto-delete cni0 before retrying, as defense-in-depth for runtime recovery * fix(containerd): use exec.CommandContext to satisfy noctx linter * fix(mcp): propagate network errors from replaceContainerSnapshot Network setup failure after snapshot replace (rollback/commit) was silently swallowed — the container would start but remain unreachable via gRPC. Return the error so callers (CreateSnapshot, RollbackVersion, etc.) surface the failure instead of reporting success.
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Summary
no IP for botwhile the system reports everything healthy.cni0bridge lingers with a zeroed MAC (00:00:00:00:00:00), causing the CNI bridge plugin to fail withcould not set bridge's mac: invalid argument. This prevents all MCP containers from obtaining network connectivity.Changes
internal/containerd/network.gointernal/mcp/manager.goManager.Start()rolls back container when IP is empty;recoverContainerIPretries up to 2× with backoffinternal/handlers/containerd.gosetupNetworkOrFailwith retry, propagate errors;ReconcileContainersno longer falsely reports "healthy"internal/mcp/mcpclient/client.goConnectingstate for >30sdevenv/server-entrypoint.shdocker/server-entrypoint.shTest plan
docker compose restart server— verify MCP containers recover network on reconcile/etc/cni/net.dconfig) — verifyStart()returns error and container is stopped