Tag Archives: iftop

CTOP

CTOP is a tool for Linux System Administration that I’ve written in Python3, that uses only the System (/proc), and not third party libraries, in order to get all the information required.

The purpose of this tool is to help to identify problems and troubleshot with a single view to a single tool that has all the typical indicators.

It provides in a single view information that is typically provided by many programs:

  • top, htop for the CPU usage, process list, memory usage
  • meminfo
  • cpuinfo
  • hostname
  • uptime
  • df to see the free space in / and the free inodes
  • iftop to see real-time bandwidth usage
  • ip addr list to see the main Ip for the interfaces
  • netstat or lsof to see the list of listening TCP Ports
  • uname -a to see the Kernel version

Other cool things it does is:

  • Identifying if you’re inside an Amazon VM, Virtual Box, Docker or lxc
  • Uses colors, and marks in yellow the warnings and in red the errors, problems like few disk space reaming or high CPU usage according to the available cores and CPUs.
  • Redraws the screen and adjust to the size of the Terminal, bigger terminal displays more information
  • It doesn’t use external libraries, and does not escape to shell. It reads everything from /proc /sys or /etc files.
  • Identifies the Linux distribution
  • Shows the most repeated binaries, so you can identify DDoS attacks (like having 5,000 apache instances where you have normally 500 or many instances of Python)
  • Indicates if an interface has the cable connected or disconnected
  • Shows the Speed of the Network Connection (useful for Mellanox cards than can operate and 200Gbit/sec, 100, 50, 40, 25, 10…)
  • It displays the local time and the Linux Epoch Time, which is universal (very useful for logs and to detect when there was an issue, for example if your system restarted, your SSH Session would keep latest Epoch captured)

Limitations:

  • It only works for Linux, not for Mac or for Windows. Although the idea is to help with Server’s Linux Administration and Troubleshot
  • The list of process of the System is read every 30 seconds, to avoid adding much overhead on the System

I decided to code name the version 0.7 as “Catalan Republic” to support the dreams and hopes and democratic requests of the Catalans people to become and independent republic.

I created this tool as Open Source and if you want to help I need people to test under different versions of:

  • RedHat (I have no longer commercial licenses)
  • Atypical Linux distributions

If you are a Cloud Provider and want me to implement the detection of your VMs, so the tool knows that is a instance of the Amazon, Google, Azure, Cloudsigma, Digital Ocean… contact me through my LinkedIn.

Monitoring an Amazon Instance, take a look at the amount of traffic sent and received

Some of the features I’m working on are parsing the logs checking for errors, kernel panics, processed killed due to lack of memory, iscsi disconnects, nfs errors, checking the logs of mysql and Oracle databases to locate errors

Linux command-line tools I usually install

Some additional command-line tools that I use to install and use on my client Systems

Apache benchmarks

To stress a Web Server

dmidecode

Is the dmi Table decoder.

For example: dmidecode -t memory

ethtool

ethtool

fatrace
Reports file access events from all running processes in real time.

flock
With flock several processes can have a shared lock at the same time, or be waiting to acquire a write lock. With lslocks from util-linux package you can get a list of these processes.

fstrim

discard unused blocks on a mounted filesystem (local or remote). Is useful for freeing blocks no longer used in ZFS zvols. That can also be achieved by mount -o discard

fuser
Show which processes use the named files, sockets, or filesystems.

git

hdparm
Get/set SATA/IDE device parameters

htop

An improved top

ifmetrics

To set the metrics of all IPV4 routes attached to a given network interface

iftop

To watch metrics for a network interface (or wireless)

iftop-wlan0

iostat

CPU and IO devices stats. I modified some collectors for telegraf and influxdb consumed by grafana for fetching the Write KB/s, Read KB/s, Bandwidth of the Magnetic Spinning drives and SSD during declustered rebuild.

iotop

iperf

Perform network throughput tests

ipmitool

iptables

iscsiadm

java (jre Oracle and OpenJDK)

ldap-utils

ldapsearch and the other tools to work with LDAP.

less
According to manpages, the opposite of more. :)
What it does is display a file, and you can scroll up/down, you can search for patterns…
Examples:
cat /etc/passwd | less
less /etc/passwd
# -n doesn’t count the lines, to save time
# For a specific Offset
less -n +500000000P /var/log/apache2/giant.log
# For 50% point
less -n +50p /var/log/apache2/giant.log

lynx

Text browser. really handy.

ltrace
To trace library calls.

mc

Midnight Commander

mc

 

md5sum

mytop

To see in real time queries and slow queries to mysql

ncdu

Show the space used by any directory and subdirectory

ncdu

ncdu-2

nginx (fpm-php) and apache

The webservers

nfs client

nmon

Offers monitoring of different aspects: Network, Disk, Processes…

open-vpn

openssh-server

parted

Partition manipulation

perf

Performance profiler.

Ie:
perf top
perf stat ls

PHP + curl + mysql (hhvm)

python-pip and pypy

pv
Pipe Viewer – is a terminal-based tool for monitoring the progress of data through a pipeline. It can be inserted into any normal pipeline between two processes to give a visual indication of how quickly data is passing through, how long it has taken, how near to completion it is, and an estimate of how long it will be until completion.

dd if=/dev/urandom | pv | dd of=/dev/null

Output:

1,74MB 0:00:09 [ 198kB/s] [      <=>                               ]

screen

sdparm
Access SCSI modes pages; read VPD pages; send simple SCSI commands

sfdisk

Utility to work with partitions that can export and import configs through STDIN and STDOUT to automate partitions operations.

slabtop
Displays Kernel slab cache information in real time.

smartctl

Utility for dealing with the S.M.A.R.T. features of the disks, knowing errors…

split
Split a file into several, based by text lines, or binary: number of bytes per file.

sshpass
SSH without typing the password. -f for reading it from a file.
sshpass -p “mypassword” ssh -o StrictHostKeyChecking=no root@10.251.35.251

In this sample passing the command ls, so this will be executed, and logout.
sshpass -p “mypassword” ssh -o StrictHostKeyChecking=no root@10.251.35.251 ls

sshuttle

A poor’s man VPN through SSH that is available for Linux and Mac OS X.

E.g.: sudo sshuttle -r carles@8.8.1.234:8275 172.30.0.0/16

Sshuttle forwards TCP and DNS but does not forward UDP or ICMP. So ping or ipmi protocol won’t work. But it does work for http, https, ssh…

Nice article on tunneling only certain things here.

strace

To trace the system calls and signals.
To redirect the output to another process use:
strace zpool status 2>&1 | less

subversion svn

systemd-cgtop and systemd-analyze

tcpdump

To see the traffic to your NIC

tee

Reads from sdtin and sends to a file and outputs to stdout as well.
For example:

find . -mtime -1 -print | grep -v "/logs/" 2>&1 | tee /var/log/results.log

timeout
Kills the process after the indicated timeout.

timeout 1000 dd if=/dev/urandom of=/dev/zvol/carles-N51-C5-D8-P2-S1/gb1000

traceroute

tree

Tree simply shows the directory hierarchy in a graphical (text mode) way. Useful to see where files and subfolders are.

xxd
Make a hexdump or do the reverse

sudo xxd /dev/nvme0n1p1 | less

zcat
Just like cat, but for compressed filed.

zcat logs.tar.gz | grep "Error"
zcat logs.tar.gz | less

zram-config

Sergey Davidoff stumbled upon a project called compcache that creates a RAM based block device which acts as a swap disk, but is compressed and stored in memory instead of swap disk (which is slow), allowing very fast I/O and increasing the amount of memory available before the system starts swapping to disk. compcache was later re-written under the name zRam and is now integrated into the Linux kernel.

http://www.webupd8.org/2011/10/increased-performance-in-linux-with.html