Category: Linux

  • lvm

    vgcreate
    pvdisplay
    lvdisplay
    lvcreate
    Resize EC2 file system with LVM
    pvcreate Device /dev/sdb excluded by a filter
    How to Remove a logical volume
    Mounting partition stored inside Logical Volume
    How to add physical volume and resize LVM

    Some related commands

    cfdisk
vgextend vg /dev/sda5
lvextend -l+100%FREE /dev/vg/lv_root
resize2fs /dev/mapper/vg-lv_root

    When I try to mount a partition I get error

    mount: unknown filesystem type ‘LVM2_member’

    This is because the partition is LVM. Got it fixed with

    root@sysresccd /root % parted -l
Model: ATA Samsung SSD 850 (scsi)
Disk /dev/sda: 500GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number  Start   End     Size    Type     File system  Flags
 1      1049kB  3146kB  2097kB  primary
 2      3146kB  527MB   524MB   primary  ext2         boot
 3      527MB   500GB   500GB   primary               lvm


root@sysresccd /root % mount /dev/sda3 /mnt
mount: unknown filesystem type 'LVM2_member'
root@sysresccd /root % lvmdiskscan
  WARNING: lvmetad is running but disabled. Restart lvmetad before enabling it!
  /dev/loop0          [     275.14 MiB]
  /dev/mapper/vg-swap [      15.75 GiB]
  /dev/sda1           [       2.00 MiB]
  /dev/mapper/vg-tmp  [       1.00 GiB]
  /dev/sda2           [     500.00 MiB]
  /dev/mapper/vg-root [     448.46 GiB]
  /dev/sda3           [     465.27 GiB] LVM physical volume
  3 disks
  3 partitions
  0 LVM physical volume whole disks
  1 LVM physical volume
root@sysresccd /root % lvscan
  WARNING: lvmetad is running but disabled. Restart lvmetad before enabling it!
  ACTIVE            '/dev/vg/swap' [15.75 GiB] inherit
  ACTIVE            '/dev/vg/tmp' [1.00 GiB] inherit
  ACTIVE            '/dev/vg/root' [448.46 GiB] inherit
root@sysresccd /root % mount /dev/vg/root /mnt
root@sysresccd /root %

  • iftop

    iftop show bandwidth usage like top show cpu and memory usage.

    To see network usage, run

    iftop

    If you have multiple network interface, you need to specify network interface to monitor, this can be done with -i option

    iftop -i eth1

    To install on CentOS, run

    yum install iftop

    For installing from source, see Install iftop from source on CentOS

    On Ubuntu

    apt -y install iftop

    To use, run iftop

    iftop

  • monit

    See gonit golang replacement for monit

    monit is a process monitoring service that monitor services, restart if required.

    https://mmonit.com/monit/

    Install monit

    monit configuration

    Here are monit rules used to monitor apache, php-fpm and MySQL on bitnami cloud server.

    # cat apache.conf
check process apache
  with pidfile "/opt/bitnami/apache2/logs/httpd.pid"
  start program = "/opt/bitnami/apache2/scripts/ctl.sh start" with timeout 90 seconds
  stop program = "/opt/bitnami/apache2/scripts/ctl.sh stop" with timeout 90 seconds

# cat php-fpm.conf
check process php-fpm
  with pidfile "/opt/bitnami/php/var/run/php5-fpm.pid"
  start program = "/opt/bitnami/php/scripts/ctl.sh start" with timeout 90 seconds
  stop program = "/opt/bitnami/php/scripts/ctl.sh stop" with timeout 90 seconds

# cat mysql.conf
check process mysql
  with pidfile "/opt/bitnami/mysql/data/mysqld.pid"
  start program = "/opt/bitnami/mysql/scripts/ctl.sh start" with timeout 90 seconds
  stop program = "/opt/bitnami/mysql/scripts/ctl.sh stop" with timeout 90 seconds

#

    monitor php-fpm

    check process php7-fpm with pidfile "/var/run/php/php7.0-fpm.pid"
    if cpu > 80% for 2 cycles then alert

  • rtorrent

    rtorrent is a command line torrent client.

    https://github.com/rakshasa/rtorrent

    This can be run from SSH connection/terminal.

    CTRL + S Start torrent.
    CTRL + Q Quit torrent.
    CTRL + D Delete selected torrent. You can use arrow keys to select torrent to delete.

    Download Magnet Link

    1. Press Enter
    2. Paste Magnet link.
    3. Press Enter.

  • Mail

    Mail Server

    These software once installed will provide complete mail server including web mail.

    Business Email

    Free Email Forwarding

    Mail DNS Settings

    Webmail

    Email Marketing

    Newsletter

    Encrypted Email

    Email Clients for Linux

    To install mail command.

    on Debian, run

    apt-get install mailutils -y

    on CentOS

    yum install mailx -y

    To send a test email, run

    echo 'Test passed.' | mail -s Test-Email [email protected]

    To specify sender address, use -r option

    echo 'Test passed.' | mail -s Test-Email -r [email protected] [email protected]

  • vnstat

    vnstat command shows bandwidth usage on your system.

    [root@server12 ~]# vnstat
Database updated: Wed Dec 13 06:51:43 2017

   eth0 since 11/04/13

          rx:  4.81 TiB      tx:  63.40 TiB      total:  68.21 TiB

   monthly
                     rx      |     tx      |    total    |   avg. rate
     ------------------------+-------------+-------------+---------------
       Nov '17     94.81 GiB |    2.02 TiB |    2.11 TiB |    7.00 Mbit/s
       Dec '17     54.05 GiB |    1.00 TiB |    1.05 TiB |    8.51 Mbit/s
     ------------------------+-------------+-------------+---------------
     estimated    136.37 GiB |    2.52 TiB |    2.65 TiB |

   daily
                     rx      |     tx      |    total    |   avg. rate
     ------------------------+-------------+-------------+---------------
     yesterday      4.45 GiB |   84.15 GiB |   88.60 GiB |    8.60 Mbit/s
         today      1.36 GiB |   25.79 GiB |   27.15 GiB |    9.22 Mbit/s
     ------------------------+-------------+-------------+---------------
     estimated      4.77 GiB |   90.35 GiB |   95.11 GiB |
[root@server12 ~]#

    Bandwidth usage by day

    [root@server12 ~]# vnstat -d

 eth0  /  daily

         day         rx      |     tx      |    total    |   avg. rate
     ------------------------+-------------+-------------+---------------
      11/14/17      3.11 GiB |   71.21 GiB |   74.32 GiB |    7.22 Mbit/s
      11/15/17      2.97 GiB |   68.86 GiB |   71.83 GiB |    6.97 Mbit/s
      11/16/17      3.14 GiB |   69.58 GiB |   72.72 GiB |    7.06 Mbit/s
      11/17/17      3.11 GiB |   72.84 GiB |   75.95 GiB |    7.37 Mbit/s
      11/18/17      2.87 GiB |   70.07 GiB |   72.94 GiB |    7.08 Mbit/s
      11/19/17      3.96 GiB |   64.32 GiB |   68.28 GiB |    6.63 Mbit/s
      11/20/17      2.71 GiB |   62.55 GiB |   65.26 GiB |    6.34 Mbit/s
      11/21/17      2.89 GiB |   66.82 GiB |   69.72 GiB |    6.77 Mbit/s
      11/22/17      2.86 GiB |   66.28 GiB |   69.14 GiB |    6.71 Mbit/s
      11/23/17      3.14 GiB |   72.26 GiB |   75.40 GiB |    7.32 Mbit/s
      11/24/17      3.26 GiB |   67.98 GiB |   71.24 GiB |    6.92 Mbit/s
      11/25/17      3.01 GiB |   66.87 GiB |   69.87 GiB |    6.78 Mbit/s
      11/26/17      3.70 GiB |   64.83 GiB |   68.53 GiB |    6.65 Mbit/s
      11/27/17      3.01 GiB |   68.27 GiB |   71.28 GiB |    6.92 Mbit/s
      11/28/17      2.88 GiB |   66.41 GiB |   69.29 GiB |    6.73 Mbit/s
      11/29/17      3.42 GiB |   73.41 GiB |   76.83 GiB |    7.46 Mbit/s
      11/30/17      2.94 GiB |   67.57 GiB |   70.52 GiB |    6.85 Mbit/s
      12/01/17      3.98 GiB |   73.32 GiB |   77.30 GiB |    7.51 Mbit/s
      12/02/17      3.86 GiB |   73.75 GiB |   77.61 GiB |    7.54 Mbit/s
      12/03/17      4.37 GiB |   79.14 GiB |   83.51 GiB |    8.11 Mbit/s
      12/04/17      3.64 GiB |   78.50 GiB |   82.14 GiB |    7.97 Mbit/s
      12/05/17      4.14 GiB |   80.11 GiB |   84.25 GiB |    8.18 Mbit/s
      12/06/17      4.61 GiB |   85.19 GiB |   89.80 GiB |    8.72 Mbit/s
      12/07/17      4.86 GiB |   85.86 GiB |   90.72 GiB |    8.81 Mbit/s
      12/08/17      4.56 GiB |   89.35 GiB |   93.91 GiB |    9.12 Mbit/s
      12/09/17      4.62 GiB |   88.69 GiB |   93.31 GiB |    9.06 Mbit/s
      12/10/17      5.11 GiB |   90.39 GiB |   95.50 GiB |    9.27 Mbit/s
      12/11/17      4.49 GiB |   88.47 GiB |   92.96 GiB |    9.03 Mbit/s
      12/12/17      4.45 GiB |   84.15 GiB |   88.60 GiB |    8.60 Mbit/s
      12/13/17      1.38 GiB |   26.12 GiB |   27.50 GiB |    9.23 Mbit/s
     ------------------------+-------------+-------------+---------------
     estimated      4.76 GiB |   90.43 GiB |   95.19 GiB |
[root@server12 ~]#

  • ip

    Ubuntu

    CentOS

    IPv6 Configuration

    Track IP location

    http://www.ip-tracker.org

    To see network interface cards on your computer, run “ip link”

    root@root1027:~# ip link
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth2:  mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether 90:e2:ba:2b:b0:5d brd ff:ff:ff:ff:ff:ff
3: eth1:  mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether 00:16:17:d2:44:6e brd ff:ff:ff:ff:ff:ff
4: eth0:  mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
    link/ether 90:e2:ba:2b:b0:0d brd ff:ff:ff:ff:ff:ff
root@root1027:~#

  • Configure Munin Node

    To install munin node on Ubuntu/Debian, run

    apt install -y munin-node

    To configure, edit file

    vi /etc/munin/munin-node.conf

    Find

    allow ^127\.0\.0\.1$

    Below this line, you need to add IP of your Munin Master. You need to convert IP to regular expression format before adding. For example, if your IP is 88.212.32.35, you need to add

    allow ^88\.212\.32\.35$

    If you want to allow from any IP, add

    allow ^.*$

    Now restart Munin node

    systemctl restart munin-node

    Add Node to Munin Master

    You need to tell your Munin master about the new node you have installed. To do this, edit file

    vi /etc/munin/munin.conf

    In this file, add

    [hostname-of-new-node-server]
    address IP_ADDR_OF_NODE
    use_node_name yes

    Now you need to wait like 5 minutes for Munin master to fetch the data. Munin master run the command /usr/bin/munin-cron to fetch data from every configured nodes.

    If you have any problem with updating data, check the log files for more info.

    /var/log/munin/munin-update.log => is the log file for munin master.

    /var/log/munin/munin-node.log => is the log file for munin node.

    Make sure you can connect to port 4949 of node server from master. If any firewall blocking, you need to open the port for munin to fetch the data.

    root@monitor:~# nc 82.211.1.93 4949
# munin node at root1272.premium-rootserver.net
# Unknown command. Try cap, list, nodes, config, fetch, version or quit
quit
root@monitor:~#

  • netdata

    To install netdata, run

    wget -O /tmp/netdata-kickstart.sh https://get.netdata.cloud/kickstart.sh
sh /tmp/netdata-kickstart.sh

    Once installed, you will be able to see server stats at

    http://your-ip:19999

    Stop/start/restart netdata

    systemctl stop netdata
systemctl start netdata
systemctl restart netdata

  • sed

    sed can be used to replace text in a file.

    sed -i 's/old-string/new-string/g'  file-name.txt

    g = Global, replace everything in a file.
    s = substitute text
    -i = update the file.

    Delete lines matching string

    To delete lines having a string and print the result.

    sed '/string to match/d' file-name.txt

    To update the file, use -i option

    sed -i '/string to match/d' file-name.txt

    Search & Replace using rpl

  • VestaCP Free Hosting Control Panel

    VestaCP Free Hosting Control Panel

    Reset VestaCP admin password
    MySQL root password in VestaCP
    Change Server Hostname in VestaCP
    VestaCP SSL for mail server
    VestaCP redirect webmail to HTTPS
    VestaCP Update
    Install PHP 7 on CentOS VestaCP
    VestaCP disable Backups
    How to change IP address of VestaCP Server

    VestaCP Free Hosting Control Panel

    You can login to VestaCP at

    https://YOUR-IP-ADDR:8083/login/
User = root
PW = your root password

    phpMyAdmin available at

    http://YOUR-IP-ADDR/phpmyadmin/

    You can see phpMyAdmin Nginx config at /etc/nginx/conf.d/phpmyadmin.inc

    Web Site DocumentRoot

    Web sites are stored in folder

    /home/USERNAME/web/DOMAINNAME/public_html

    Log Files

    /var/log/nginx/domains/ => stores Nginx Access and error logs for hosted web sites.

    Configuration Files

    php-fpm configurations for each web sites are stored in /etc/php-fpm.d/DOMAIN.conf, each web sites runs php-fpm in its own pool. Here is sample config

    [root@localhost ~]# cat /etc/php-fpm.d/localhost.localdomain.conf 
[localhost.localdomain]
listen = 127.0.0.1:9001
listen.allowed_clients = 127.0.0.1

user = admin
group = admin

pm = dynamic
pm.max_children = 50
pm.start_servers = 3
pm.min_spare_servers = 2
pm.max_spare_servers = 10

env[HOSTNAME] = $HOSTNAME
env[PATH] = /usr/local/bin:/usr/bin:/bin
env[TMP] = /tmp
env[TMPDIR] = /tmp
env[TEMP] = /tmp
[root@localhost ~]#

    Apache/Nginx configuration in folder : /home/admin/conf/web (admin is user, if you have other users, check folder for the user)

    VestaCP Installer Compromised

    See Hosting Control Panel

  • Install PHP 7.1 php-fpm from source

    Lets install the requirements.

    On CentOS, run

    yum -y install libxml2-devel libcurl-devel libmcrypt-devel openssl-devel
yum -y install libjpeg-turbo-devel libpng-devel freetype-devel libtidy-devel

    Before you can install, you need to check MySQL socket location. To do this, run following command in MySQL command prompt.

    show variables like '%socket%;

    Find MySQL socket

    Download and install PHP 7.1 from source

    mkdir /usr/local/src
cd /usr/local/src
wget http://php.net/get/php-7.1.12.tar.gz/from/this/mirror -O php-7.1.12.tar.gz
tar xf php-7.1.12.tar.gz
cd php-7.1.12
make clean
./configure --prefix=/usr/serverok/php-7.1.12 \
--with-config-file-path=/usr/serverok/php-7.1.12/etc \
--with-mysql-sock=/var/lib/mysql/mysql.sock \
--with-pdo-mysql \
--with-mysqli \
--enable-cgi \
--with-zlib \
--with-gettext \
--enable-ftp \
--enable-calendar \
--enable-bcmath \
--enable-sockets \
--with-curl \
--with-gd \
--with-jpeg-dir=/usr/local \
--enable-mbstring \
--with-freetype-dir=/usr/local \
--with-mhash=/usr/local --enable-exif \
--with-mcrypt=/usr \
--with-tidy \
--with-openssl \
--enable-zip \
--enable-fpm
make && make install

    Copy the configuration files

    cp /usr/serverok/php-7.1.12/etc/php-fpm.conf.default /usr/serverok/php-7.1.12/etc/php-fpm.conf
cp /usr/serverok/php-7.1.12/etc/php-fpm.d/www.conf.default /usr/serverok/php-7.1.12/etc/php-fpm.d/www.conf
cp /usr/local/src/php-7.1.12/php.ini-development /usr/serverok/php-7.1.12/etc/php.ini

    Now you will be able to start php-fpm by running

    /usr/serverok/php-7.1.12/bin/php

    By default php-fpm will run using tcp port 9000, it is better to change it to use unix socket, for this 

    vi /usr/serverok/php-7.1.12/etc/php-fpm.d/www.conf

    Find

    listen = 127.0.0.1:9000

    Replace with

    listen = /var/run/php-fpm/proxy.sock

    php-fpm user

    You need to configure the user account used to run php-fpm, if you don’t use proper account, you may get permission errors.

    The account you use vary depending on OS, Web server. For example, nginx use account nginx. Apache on Ubuntu/Debian use www-data. Apache on CentOS use nobody.

    Here is what i have on a server running Nginx web server

    [root@vps154294 ~]# cat /usr/serverok/php-7.1.12/etc/php-fpm.d/www.conf | grep nginx
user = nginx
group = nginx
listen.owner = nginx
listen.group = nginx
[root@vps154294 ~]#

    Systemd Service

    To easily manage php-fpm, lets create a php-fpm.service file.

    Before we do this, edit 

    vi /usr/serverok/php-7.1.12/etc/php-fpm.conf

    Find

    ;pid = run/php-fpm.pid

    Add below

    pid = /run/php-fpm/php-fpm.pid

    Find

    ;error_log = log/php-fpm.log

    Add below

    error_log = /var/log/php-fpm/error.log

    Save and exit.

    Now lets create file /usr/lib/systemd/system/php-fpm.service

    vi /usr/lib/systemd/system/php-fpm.service

    Add following content

    [Unit]
Description=PHP FastCGI process manager
After=syslog.target network.target

[Service]
PIDFile=/run/php-fpm/php-fpm.pid
ExecStartPre=/bin/mkdir --parents /run/php-fpm
ExecStart=/usr/serverok/php-7.1.12/sbin/php-fpm --nodaemonize
ExecReload=/bin/kill -USR2 $MAINPID
Type=simple

[Install]
WantedBy=multi-user.target

    Enable php-fpm with

    systemctl enable php-fpm

    Now you will be able to use systemctl to start/stop/restart php-fpm

    systemctl start php-fpm
systemctl stop php-fpm
systemctl restart php-fpm

    systemctl status php-fpm