System Crashing¶

Check the health of RAM¶

memtest 86 tool is run in boot instead of normal operating system.

System crash log files are located in /var/log in linux and for windows we can look at the Event Viewer tool.

strace (system trace) can also be used in linux to find out which system call is made during the crash to identify the root cause.

Configuration management Cloud¶

Configuration management is an Automation technique which let manage computers at a large scale.

puppet is current industry standard for config-management.

disk usage¶

To check disk usage of your system using python use

import shutil
disk_usage = shutil.disk_usage("/")
print(disk_usage) 

>>usage(total=982240026624, used=45239689216, free=887029821440)

cpu usage¶

To check cpu usage use psutil in python

strace¶

gives the trace of systemcalls made by any program and tell the result of each of the calls made by the program.

strace trial.py

mmap(NULL, 172296, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7eff145b3000
mmap(0x7eff145b6000, 110592, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x3000) = 0x7eff145b6000
mmap(0x7eff145d1000, 45056, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e000) = 0x7eff145d1000
mmap(0x7eff145dc000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x28000) = 0x7eff145dc000
close(3)                                = 0
mprotect(0x7eff145dc000, 4096, PROT_READ) = 0
mprotect(0x7eff145e8000, 4096, PROT_READ) = 0
munmap(0x7eff145fd000, 26071)           = 0
statfs("/", {f_type=EXT2_SUPER_MAGIC, f_bsize=4096, f_blocks=239804694, f_bfree=228791752, f_bavail=216591919, f_files=60981248, f_ffree=60855621, f_fsid={val=[0x7fa55e7a, 0x8782ee03]}, f_namelen=255, f_frsize=4096, f_flags=ST_VALID|ST_RELATIME}) = 0
write(1, "usage(total=982240026624, used=4"..., 63usage(total=982240026624, used=45109010432, free=887160500224)
) = 63
rt_sigaction(SIGINT, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=SA_RESTORER|SA_ONSTACK, sa_restorer=0x7eff14cc1520}, {sa_handler=0x561cf4939980, sa_mask=[], sa_flags=SA_RESTORER|SA_ONSTACK, sa_restorer=0x7eff14cc1520}, 8) = 0
munmap(0x7eff1470d000, 151552)          = 0
exit_group(0)                           = ?
+++ exited with 0 +++

Output shows a lot of systemcall details.

strace -o output.trace trial.py

This time the output of the strace command is stored in a trace file.

see disk input and output¶

top
iotop -> show the disk usage
iostat
vmstat
ionice


iftop -> shows current traffic on network interfaces
nice -> modify the priority of a process inorder to access CPU time.
renice -> modify the priority of a running process

pidof jellyfin # prints the PID of the running process named jellyfin


ps ax | less # shows all the running process on computer
# less is used to scroll through the command line output

Using python to interact with OS¶

Use perato principle determine which task to automate

Some of the useful system adm function in python¶

shutil.disk_usage
psutil Module

Configuration management and the Cloud¶

In this course we learn puppet which is current industry standard for configuration management.