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How to harden a TiDB container (and is pingcap/tidb:v8.5.0 safe for untrusted workloads?)

TiDB is a distributed SQL database that speaks the MySQL protocol, so its container fronts your application's queries and belongs among the tightest things you run. A stock docker run pingcap/tidb:v8.5.0 is not: graded on IronClaw's seven-dimension containment scale it scores 48 of 100, grade D (porous). Higher is safer. A short list of runtime flags takes the same image to 100 of 100, grade A on a single-instance deployment whose components share one private network. Here are the exact gaps and fixes from the scan data.

Graded from a read-only inspect of a running container started from pingcap/tidb:v8.5.0 with plain docker run defaults, its entrypoint overridden with sleep purely to keep it alive. The scan itself executes nothing inside the container. It is the same data behind its isolation scorecard. How scoring works →

Where the default configuration leaks

ironctl scan grades seven independent containment boundaries. On a default docker run pingcap/tidb:v8.5.0, four fail or warn:

Dimension Verdict Score What the scan found
Non-root user (uid != 0) ❌ FAIL 0/15 runs as root (uid 0); a container escape starts with host-uid 0
Dropped capabilities ❌ FAIL 4/20 default capability set retained (CAP_NET_RAW, CAP_MKNOD, and more)
Seccomp profile ✅ PASS 15/15 seccomp profile active
Network isolation / egress ⚠️ WARN 4/15 network=bridge: outbound egress is possible
Read-only root filesystem ❌ FAIL 0/10 root filesystem is writable
No docker.sock exposure ✅ PASS 15/15 no control socket mounted
No shared host namespaces ✅ PASS 10/10 no host PID/IPC/network sharing

The sharpest edges are root, the retained capabilities, and the writable rootfs: a SQL-parser or plugin CVE that lands code execution lands it as uid 0, with CAP_NET_RAW and friends, on a filesystem it can rewrite to persist.

Harden it: the exact --fix remediation

ironctl scan my-tidb --fix prints one remediation per failed dimension, then one hardened run. For pingcap/tidb:v8.5.0:

  • --user 65532:65532 (Non-root, +15): run the tidb-server process as an unprivileged uid.
  • --cap-drop=ALL (Dropped capabilities, +16): drop every Linux capability; add back only what the workload provably needs. The SQL layer needs none of the defaults.
  • --read-only --tmpfs /tmp (Read-only rootfs, +10): the tidb-server is stateless (storage lives in TiKV), so a read-only rootfs with a /tmp scratch mount removes the persistence surface cleanly.
  • --network=none (Network isolation, +11): when the whole stack (PD, TiKV, tidb-server) sits on one private compose network with no default route out, the tidb-server needs no host egress. Cutting it is the dimension that takes a single-machine deployment to a full A.

Before and after

# Before: 48/100, grade D
docker run -d --name tidb pingcap/tidb:v8.5.0

# After: 100/100, grade A
docker run -d --name tidb-hardened \
  --user 65532:65532 \
  --cap-drop=ALL \
  --security-opt=no-new-privileges \
  --read-only --tmpfs /tmp \
  --network=none \
  pingcap/tidb:v8.5.0

Rescan: ironctl scan tidb-hardened reports 100/100 grade A. A 52-point swing with no custom image build, just the right flags.

Running a production cluster? A multi-node TiDB where tidb-server reaches PD and TiKV across hosts, or where remote MySQL clients connect, needs a real network, so --network=none is wrong there. Keep the other four fixes and attach a scoped private network; the honest ceiling is then 89/100, grade B, with the network dimension held at a WARN. A single-machine stack behind one private network reaches the full A.

Verify it on your own database

# install (Homebrew)
brew install ironsecco/ironclaw/ironclaw

# grade your running container, then print the fixes
ironctl scan my-tidb
ironctl scan my-tidb --fix

ironctl scan also reads a docker-compose.yml service or a Kubernetes manifest, so you can grade the TiDB in your stack, not just a bare docker run.

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