Inspect a machine#

A runbook for answering "what is this box?" with only the tools in a minimal Alpine Linux image (BusyBox). The machine here is the page's own virtual machine, so the numbers describe it, not your computer.

Who and where#

echo "user: $(id -un) (uid $(id -u))"
echo "host: $(hostname)"
uname -srm
cat /etc/alpine-release

CPU#

The machine has one virtual CPU.

grep -c '^processor' /proc/cpuinfo
head -n 12 /proc/cpuinfo

Memory#

head -n 5 /proc/meminfo
echo
free -m

MemAvailable is the number to watch. MemFree ignores memory the kernel can take back from caches.

Disks and mounts#

df -h

mount | head -n 20

Look for the root file system and for tmpfs mounts such as /tmp and /dev/shm. The kernel's own view is in /proc/mounts.

Processes#

ps
echo
uptime

Load and uptime in the raw#

cat /proc/loadavg
cat /proc/uptime

The three load numbers are the 1, 5 and 15 minute averages, then running and total tasks, then the last process id. The two uptime numbers are seconds up and seconds idle.

Checklist#

1. Identify the system (uname, /etc/*-release).
2. Count CPUs and read MemAvailable.
3. Check free space with df -h before you write anything big.
4. Read mount for read-only or unexpected mounts.
5. List processes and the load average.