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name: verify-ssi description: Verify Single Step Instrumentation (SSI) is working end-to-end on Linux hosts — SSI automatically instruments applications for APM without code changes. Only use after enable-ssi has run. metadata: version: "1.0.0" author: datadog-labs repository: https://github.com/datadog-labs/agent-skills tags: datadog,apm,linux,ssi,verification,instrumentation,ld-preload alwaysApply: "false"

Verify APM SSI on Linux

Before doing anything else: Fully resolve all variables in ## Context to resolve before acting. Do not begin Step 1 until every variable has a concrete value.

Triggers

Invoke this skill when the user expresses intent to:

• Confirm SSI is working after installing the Datadog Agent on Linux
• Check whether a Linux process is being instrumented
• Verify the tracer is running and reporting telemetry

Do NOT invoke this skill if:

• SSI has not been enabled yet — run agent-install first
• Services have not been restarted since the agent was installed — restart them first, then verify

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Prerequisites

• agent-install is complete
• Application services have been restarted since the agent was installed

pup-cli: check, install, and authenticate

Claude runs

pup --version

If not found:

Claude runs

brew tap datadog-labs/pack
brew install pup

Check auth:

pup auth status --site <DD_SITE>

If not authenticated:

Claude runs

pup auth login --site <DD_SITE>

This opens a browser tab for OAuth. Complete the login there — Claude will continue once the command exits.

If valid token — proceed. ERROR: No browser available: export DD_APP_KEY=<your-app-key>

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Context to resolve before acting

Variable	How to resolve
DD_HOSTNAME	Hostname as Datadog sees it — from sudo datadog-agent status output
SERVICE_NAME	Expected service name in APM — ask the user
ENV	Environment tag — ask the user
DD_SITE	grep "^site:" /etc/datadog-agent/datadog.yaml via SSH, or ask the user
SSH_KEY	Path to SSH private key
SSH_USER	SSH username
SSH_HOST	Hostname or IP of the target host

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Step 1: Confirm the Process is Injected

Use /proc/<pid>/maps — this is the authoritative check. It shows the actual shared libraries loaded into the running process, which is the only way to confirm the launcher and tracer .so files were actually loaded.

Claude runs

ssh -o StrictHostKeyChecking=no -i <SSH_KEY> <SSH_USER>@<SSH_HOST> \
  "pgrep -a -f '<SERVICE_NAME>' | head -5"

Use the PID from above:

ssh -o StrictHostKeyChecking=no -i <SSH_KEY> <SSH_USER>@<SSH_HOST> \
  "sudo cat /proc/<PID>/maps | grep -E 'launcher|apm-library|datadog'"

If the output includes both the launcher (e.g. launcher.preload.so) and a language library (e.g. apm-library-python) — injection succeeded for this process.

ERROR: Launcher present but no language library — launcher ran but couldn't inject. Check for injection errors:

Claude runs

pup apm troubleshooting list --hostname <DD_HOSTNAME> --timeframe 1h

ERROR: Neither present — process was not injected. Check /etc/ld.so.preload:

ssh -o StrictHostKeyChecking=no -i <SSH_KEY> <SSH_USER>@<SSH_HOST> "cat /etc/ld.so.preload"

If empty — install did not set up the launcher. Re-run the install script with DD_APM_INSTRUMENTATION_ENABLED=host. If non-empty but the process still isn't injected — the process was started before the launcher was installed. Restart the service and recheck.

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Step 2: Confirm the Agent is Receiving Traces

Claude runs

ssh -o StrictHostKeyChecking=no -i <SSH_KEY> <SSH_USER>@<SSH_HOST> \
  "sudo datadog-agent status 2>&1 | grep -A 15 'APM Agent'"

Healthy output shows:

• feature_auto_instrumentation_enabled: true
• Receiver (previous minute) with > 0 traces

ERROR: feature_auto_instrumentation_enabled: false — SSI not active on the agent. Check apm_config in /etc/datadog-agent/datadog.yaml.

ERROR: Receiver (previous minute): 0 — agent running but no traces yet. Generate traffic first (see Step 3), then recheck.

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Step 3: Confirm the Service is Visible in Datadog

Claude runs

DD_SITE=<DD_SITE> pup apm services list --env <ENV> --from 1h

If <SERVICE_NAME> appears with isTraced: true — traces are reaching the Datadog backend.

Flask / ddtrace v3 naming note: With ddtrace >=3.x, Flask spans are emitted as service:flask rather than service:<DD_SERVICE>. The DD_SERVICE value appears as base_service on the spans. If you set DD_SERVICE=my-app, search for service:flask in the APM UI — the service list will show flask, not my-app. Check the base_service tag to confirm it matches your DD_SERVICE.

ERROR: Service missing — generate traffic to trigger trace creation:

Claude runs

ssh -o StrictHostKeyChecking=no -i <SSH_KEY> <SSH_USER>@<SSH_HOST> \
  "sudo ss -tlnp 2>/dev/null | grep <PID> || sudo netstat -tlnp 2>/dev/null | grep <PID>"

Use the port from above:

ssh -o StrictHostKeyChecking=no -i <SSH_KEY> <SSH_USER>@<SSH_HOST> \
  "for i in \$(seq 1 10); do curl -s -o /dev/null http://localhost:<PORT>/; done"

Wait 30 seconds, then retry:

DD_SITE=<DD_SITE> pup apm services list --env <ENV> --from 10m
DD_SITE=<DD_SITE> pup traces search --query "service:<SERVICE_NAME>" --from 10m --limit 5

ERROR: Still missing — check for injection errors and go to troubleshoot-ssi:

pup apm troubleshooting list --hostname <DD_HOSTNAME> --timeframe 1h

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Done

Exit when ALL of the following are true:

• Step 1: launcher + language library both visible in /proc/<PID>/maps
• Step 2: agent APM receiver shows > 0 traces/min
• Step 3: service appears in pup apm services list

If any check fails, go to troubleshoot-ssi.

When all steps pass, automatically proceed to onboarding-summary now — do not ask the user for permission.

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Security constraints

• Never write a raw API key into any file or chat message
• Always confirm before restarting production services