Tencent Cvm Log Analyzer

Tencent Cloud CVM Log Analyzer

Overview

Triage and analyze logs from a Tencent Cloud CVM (Linux) instance. Collect a time-bounded, mostly read-only slice of system/web/app/auth logs, summarize anomalies (errors, spikes, suspicious IPs), and produce an actionable incident report.

Quick start (ask for these)

• CVM public IP / hostname (and SSH port if not 22)
• SSH user (depends on image: ubuntu / root / centos) + private key path (preferred), or TAT output (fallback)
• Time window (e.g. last 2h / last 24h) and server timezone
• Observed symptoms (e.g. 502 spikes, CPU 100%, login brute-force)
• Stack details: nginx/apache, docker, systemd service name, custom app log path

Authentication (local-only)

Default key path (do not commit/copy the key into this skill):

• Private key: <PATH_TO_PRIVATE_KEY>

Ensure key permissions are strict:

chmod 600 <PATH_TO_PRIVATE_KEY>

Default target (local-only)

This skill assumes your current CVM target is:

• HostName: <YOUR_CVM_PUBLIC_IP_OR_HOSTNAME>
• Port: 22 (or your SSH port)
• User: <YOUR_SSH_USER> (often root / ubuntu)

Suggested ~/.ssh/config entry:

Host tencent-cvm
  HostName <YOUR_CVM_PUBLIC_IP_OR_HOSTNAME>
  Port 22
  User <YOUR_SSH_USER>
  IdentityFile <PATH_TO_PRIVATE_KEY>
  IdentitiesOnly yes

Then test:

ssh tencent-cvm 'echo ok'

One-off SSH example:

ssh -i <PATH_TO_PRIVATE_KEY> -p 22 <YOUR_SSH_USER>@<YOUR_CVM_PUBLIC_IP_OR_HOSTNAME> 'echo ok'

Workflow decision tree

1. Prefer SSH access if possible.
2. If SSH is blocked, use Tencent Cloud Automation Tools (TAT/云助手) to run the same read-only commands and paste the outputs.
3. If logs are enormous, avoid copying full logs; extract a sample (tail) or aggregate counts (awk/grep).

Workflow: Collect → Analyze → Report

1) Establish context (always)

Run on the server (read-only):

date
timedatectl 2>/dev/null || true
uname -a
cat /etc/os-release 2>/dev/null || true
ps -p 1 -o comm=

Capture current health:

uptime
df -h
free -h 2>/dev/null || true

If you see OOM / reboots, check swap (enabling swap changes system state; ask before doing it):

swapon --show
ls -lah /swapfile 2>/dev/null || true
file /swapfile 2>/dev/null || true

If systemd is present, list failed units:

systemctl --failed --no-pager 2>/dev/null || true

2) System log triage

If systemd is present:

journalctl -p warning..emerg --since "24 hours ago" --no-pager | tail -n 200

Otherwise check syslog files (paths vary by distro; see references/log-locations.md):

sudo tail -n 200 /var/log/syslog 2>/dev/null || true
sudo tail -n 200 /var/log/messages 2>/dev/null || true

3) SSH / auth / security triage

Check for brute-force attempts and new logins:

sudo tail -n 200 /var/log/auth.log 2>/dev/null || sudo tail -n 200 /var/log/secure 2>/dev/null || true
sudo grep -E "Failed password|Invalid user|Accepted" /var/log/auth.log /var/log/secure 2>/dev/null | tail -n 200 || true
last -a | head -n 20

If the user is worried about an attack, also list listening ports:

ss -tulpen 2>/dev/null || netstat -tulpen 2>/dev/null || true

4) Web server triage (nginx/apache)

Start with error logs:

sudo tail -n 200 /var/log/nginx/error.log 2>/dev/null || true
sudo tail -n 200 /var/log/apache2/error.log 2>/dev/null || true

For access logs, avoid pasting the full file. Create a small sample on the server:

sudo tail -n 200000 /var/log/nginx/access.log > /tmp/nginx-access.tail.log

On your local machine, run the bundled analyzer from this skill folder:

cd <PATH_TO_SKILL_FOLDER>

Then analyze locally (option A: scp):

## Using ~/.ssh/config alias (recommended)
scp tencent-cvm:/tmp/nginx-access.tail.log /tmp/nginx-access.tail.log
python3 scripts/nginx_access_summary.py /tmp/nginx-access.tail.log

## One-off (no ssh config)
scp -i <PATH_TO_PRIVATE_KEY> <SSH_USER>@<YOUR_CVM_PUBLIC_IP_OR_HOSTNAME>:/tmp/nginx-access.tail.log /tmp/nginx-access.tail.log
python3 scripts/nginx_access_summary.py /tmp/nginx-access.tail.log

Or analyze via ssh pipe (option B):

## Using ~/.ssh/config alias (recommended)
ssh tencent-cvm 'sudo tail -n 200000 /var/log/nginx/access.log' | python3 scripts/nginx_access_summary.py -

## One-off (no ssh config)
ssh -i <PATH_TO_PRIVATE_KEY> <SSH_USER>@<YOUR_CVM_PUBLIC_IP_OR_HOSTNAME> 'sudo tail -n 200000 /var/log/nginx/access.log' | python3 scripts/nginx_access_summary.py -

5) App/service logs (systemd or docker)

For a systemd service:

journalctl -u <service-name> --since "24 hours ago" --no-pager | tail -n 400

For a docker container:

docker ps --format 'table {{.Names}}\t{{.Image}}\t{{.Status}}'
docker logs --since 24h <container-name> 2>&1 | tail -n 400

Output format (produce a report)

Write a Markdown report with:

• Time window + timezone
• Symptom summary (what broke, impact)
• Key findings (top errors, top endpoints, top suspicious IPs)
• Likely root causes (ranked)
• Next actions (commands to run, configs to check, mitigations)

Safety rules

• Prefer read-only commands and time-bounded queries (--since, tail).
• Ask before running any command that changes state (restart services, rotate/truncate logs, firewall changes, package installs).
• Redact secrets in shared logs (tokens, cookies, passwords, private URLs, internal IPs if needed).

Resources

• scripts/nginx_access_summary.py: Summarize nginx access logs (status codes, IPs, endpoints, request rate).
• references/log-locations.md: Common log locations on Linux (systemd/nginx/docker/auth).
• references/triage-commands.md: Safe read-only commands for incident triage.