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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.

Every number here comes from a read-only docker inspect of pingcap/tidb:v8.5.0, the same data behind its isolation scorecard. No workload is executed. 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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