Stopping ALL your proxmox services in Proxmox PVE 5.x

Sometime you just need to STOP promox pve services in your hardware nodes because they froze or not functioning properly. These commands below will help you stop all your proxmox services:

killall -9 corosync
systemctl stop pve-cluster
systemctl stop pvedaemon
systemctl stop pveproxy
systemctl stop pvestatd

Restart all Proxmox services in PVE 5.x

Sometime you just need to restart promox pve services in your hardware nodes because they froze or not functioning properly. These commands below will help you restart all your proxmox services:

killall -9 corosync
systemctl restart pve-cluster
systemctl restart pvedaemon
systemctl restart pveproxy
systemctl restart pvestatd

Setup outgoing email using Rackspace SMTP for your ubuntu server using Postfix

Follow this very easy steps to send outgoing emails from your ubuntu server using Rackspace Email server SMTP.

Step 1 - Prepare required software

aptitude update apt-get install postfix libsasl2-modules

Step 2 - Configure Postfix's main.cf

Add the following to /etc/postfix/main.cf:

 relayhost = secure.emailsrvr.com
 smtp_sasl_auth_enable=yes
 smtp_sasl_password_maps=hash:/etc/postfix/sasl_passwd
 smtp_sasl_mechanism_filter = AUTH LOGIN
 smtp_sasl_security_options =

Step 3 - Set your username and password into sasl_password

Add the Rackspace Email username and password to /etc/postfix/sasl_passwd by running these commands:

echo 'secure.emailsrvr.com username@domain.com:secretpassword' > /etc/postfix/sasl_passwd
chmod 600 /etc/postfix/sasl_passwd
postmap /etc/postfix/sasl_passwd

Step 4 - Restart Postfix

service postfix restart


Step 5 - Send test email


echo "My message body" | mail -s "Test Email Subject" somebody@gmail.com



That is all... 5 easy steps will get your server sending email reliably using Rackspace Email account!

Preparation commands I do for every new Ubuntu Server

For every Ubuntu server I build, I always take time to configure it should have a good base.  A good base for any type of server is having its Time Zone, Locales, and Character sets set correctly.  Another software which is usually required is the Ubuntu PPA software repository system.

Here are the commands I usually execute for every Ubuntu server I create:

UPDATE AND UPGRADE

apt-get update
apt-get -y dist-upgrade

SETTING TIME ZONE

dpkg-reconfigure tzdata

SETTING LOCALES

locale-gen en_US en_US.UTF-8

INSTALL PPA REPOSITORY SUPPORT

apt-get install software-properties-common python-software-properties

UNINSTALL POSTFIX (if you don't need to send email)

service stop postfix

apt-get remove postfix

apt-get purge

apt-get autoclean

INSTALL FREE FOREVER SSL CERTIFICATE (in 5 min)

Quick how to guide to create EXT4 partition from a free disk partition using LVM

This is a quick guide to create a usable EXT4 partition from an unused disk partition with LVM.

In this example my UNUSED DISK PARTITION is on /dev/sda4

*** THIS WILL ERASE ALL CONTENT IN /dev/sda4 ***

STEP 1 - PREPARE THE PARTITION TO TYPE: linux LVM

fdisk /dev/sda

change partition type by entering 't', '4', '31'

't' is for changing partition type
'4' is to select partition #4
'31' is to select Linux LVM partition type

check to make sure partition type has been set properly by pressing 'p' then ENTER, you should see something like this (I highlighted partition 4 which shows Linux LVM:

/dev/sda1      2048      4095      2048     1M BIOS boot
/dev/sda2      4096    528383    524288   256M EFI System
/dev/sda3    528384  33554432  33026049  15.8G Linux LVM
/dev/sda4  33556480 586072334 552515855 263.5G Linux LVM

STEP 2 - CREATE PV, then VG, then LV 

Every LVM volume involves creating these 3 types of sub lvm systems:

1. Physical volume (PV)
2. Volume group (VG) (I named mine vg_ssd_data)
3. Logical volume (LV) (I named mine lv_ssd_data)

Type the following commands:

pvcreate /dev/sda4

vgcreate vg_ssd_data /dev/sda4

lvcreate -l 100%FREE -n lv_ssd_data vg_ssd_data

lvs   (this command is optional - only to display your logical volumes - see below)

  LV          VG          Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  data        pve         twi-a-tz--   8.25g             0.00   0.55
  root        pve         -wi-ao----   3.75g
  swap        pve         -wi-ao----   1.88g
  lv_ssd_data vg_ssd_data -wi-a----- 263.46g

STEP 3 - GET YOUR DEVICE MAPPER NAME

Enter the following command to display all your logical volumes, to get your device mapper path.

(I highlighted my logical volume which shows the device mapper path)

lvdisplay

  --- Logical volume ---

  LV Path                /dev/vg_ssd_data/lv_ssd_data

  LV Name                lv_ssd_data

  VG Name                vg_ssd_data

  LV UUID                dDqnRP-1wt2-UHcI-gE3T-WYle-HtNB-cWbfis

  LV Write Access        read/write

  LV Creation host, time e1, 2018-02-18 10:18:07 -0600

  LV Status              available

  # open                 0

  LV Size                263.46 GiB

  Current LE             67445

  Segments               1

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:5

  --- Logical volume ---

  LV Path                /dev/pve/swap

  LV Name                swap

  VG Name                pve

  LV UUID                QzAL07-mdzD-RoH5-ulXa-gwGt-FtTN-XRhA4q

  LV Write Access        read/write

  LV Creation host, time proxmox, 2017-12-02 20:53:30 -0600

  LV Status              available

  # open                 2

  LV Size                1.88 GiB

  Current LE             480

  Segments               1

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:0

  --- Logical volume ---

  LV Path                /dev/pve/root

  LV Name                root

  VG Name                pve

  LV UUID                2LuMFi-XzY9-TWNf-uiH3-qdAc-Y5Xa-r6ajdz

  LV Write Access        read/write

  LV Creation host, time proxmox, 2017-12-02 20:53:30 -0600

  LV Status              available

  # open                 1

  LV Size                3.75 GiB

  Current LE             960

  Segments               1

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:1

  --- Logical volume ---

  LV Name                data

  VG Name                pve

  LV UUID                hBfLjZ-Zqib-TMwJ-7dQh-qBrJ-7XHZ-D1G2lQ

  LV Write Access        read/write

  LV Creation host, time proxmox, 2017-12-02 20:53:30 -0600

  LV Pool metadata       data_tmeta

  LV Pool data           data_tdata

  LV Status              available

  # open                 0

  LV Size                8.25 GiB

  Allocated pool data    0.00%

  Allocated metadata     0.55%

  Current LE             2112

  Segments               1

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:4

STEP 4 - MAKE THE EXT4 PARTITION

The command below will create the EXT4 partition:

mkfs.ext4 /dev/vg_ssd_data/lv_ssd_data

the result should look similar to this:

mke2fs 1.43.4 (31-Jan-2017)

Discarding device blocks: done

Creating filesystem with 69063680 4k blocks and 17268736 inodes

Filesystem UUID: 123a79fb-226e-45b2-ab97-bdd8df335538

Superblock backups stored on blocks:

32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,

4096000, 7962624, 11239424, 20480000, 23887872

Allocating group tables: done

Writing inode tables: done

Creating journal (262144 blocks): done

Writing superblocks and filesystem accounting information: done

STEP 5 - CREATE THE DIRECTORY WHERE WE WILL MOUNT THE PARTITION

The following 2 commands will create a directory and set its partition to 777 (all access - this is just for my example - you probably want to restrict your permission)

mkdir /mnt/ssd_data

chmod -R 777 /mnt/ssd_data

STEP 6 - GET UUID USING COMMAND BLKID

The following command 'blkid' will show you the UUID which you will need to mount your newly created partition.

blkid

My result looks like:

/dev/sda2: UUID="72B0-472C" TYPE="vfat" PARTUUID="43003f1e-9cbd-461c-ba1f-b288196eaf8d"

/dev/sda3: UUID="ceYVkY-WxbN-UQME-i6Gt-frKB-rDeW-StrMMz" TYPE="LVM2_member" PARTUUID="ac2082b2-aed1-432d-8102-86246ab4d738"

/dev/mapper/pve-swap: UUID="d44d4cfc-c6b2-4f75-b24a-a6ec99e6d748" TYPE="swap"

/dev/mapper/pve-root: UUID="d41800f7-bf3a-42fb-bbd2-9f4519d99bd6" TYPE="ext4"

/dev/sda1: PARTUUID="491629a5-bea8-4a61-84a7-b4610e8b4607"

/dev/sda4: UUID="Iv347n-th9t-fC3v-UpUc-bHFN-LKOA-shD5Eg" TYPE="LVM2_member" PARTUUID="bfc4c91b-148b-429c-a9eb-b6d80a1dd685"

/dev/sdb: PTUUID="05ca81c9-9745-4fb2-bd15-ced9e1525169" PTTYPE="gpt"

/dev/sdc: PTUUID="8e2952c8-96a6-4c41-a9a8-0ae9cde93182" PTTYPE="gpt"

/dev/mapper/vg_ssd_data-lv_ssd_data: UUID="123a79fb-226e-45b2-ab97-bdd8df335538" TYPE="ext4"

STEP 6 - ADDING YOUR PARTITION TO FSTAB

The following command, you will edit your FSTAB (filesystem table) to add a line which will tell your computer to AUTOMATICALLY MOUNT the partition everytime the computer starts (cold / warm start)

nano /etc/fstab

add the following line (note the UUID in RED and DIRECTORY in BLUE):

UUID=123a79fb-226e-45b2-ab97-bdd8df335538 /mnt/ssd_data ext4 defaults,noatime,nodiratime,noacl,data=writeback,barrier=0,nobh,errors=remount-ro 0 2

STEP 7 - FINALLY! MOUNT AND CHECK YOUR PARTITION FREE DISK SPACE

The following command will mount all your partition by reading your settings from the filesystem table (/etc/fstab)

mount -a

(mount -a does not have any output when successful)

The following command will show FREE DISK SPACE for all your MOUNTED PARTITIONS:

df -h

Filesystem                           Size  Used Avail Use% Mounted on

udev                                  24G     0   24G   0% /dev

tmpfs                                4.8G  9.2M  4.8G   1% /run

/dev/mapper/pve-root                 3.7G  1.8G  1.7G  52% /

tmpfs                                 24G   45M   24G   1% /dev/shm

tmpfs                                5.0M     0  5.0M   0% /run/lock

tmpfs                                 24G     0   24G   0% /sys/fs/cgroup

/dev/fuse                             30M   24K   30M   1% /etc/pve

tmpfs                                4.8G     0  4.8G   0% /run/user/0

/dev/mapper/vg_ssd_data-lv_ssd_data  259G   61M  246G   1% /mnt/ssd_data

PHP 5.4 5.5 5.6 Nginx PHP5-FPM - 502 Bad Gateway Issue Solved

I have been battling this issue:

PHP 5.4 5.5 5.6 Nginx PHP5-FPM - 502 Bad Gateway Issue Solved

for several days.  Here are the symptoms:

When you execute a PHP script it does not show any output on the browser, just WHITE PAGE!

In the Nginx log you will see error log like this:

2018/02/01 12:56:18 [error] 16526#16526: *122 readv() failed (104: Connection reset by peer) while reading upstream, client:

In the PHP FPM log you will see error log like this:

[pool www] child 21970 exited on signal 11 (SIGSEGV) after 57.041592 seconds from start

This was very difficult to troubleshoot because I literally was getting no useful clue of what is happening.

I tried to upgrade my outdated PHP from 5.4.x to 5.6 but unsuccessful because my Ubuntu server version was so old (12.04 LTS Precise Pangolin) :-(

So I dediced to keep troublshotting by process of elimination.

The breakthrough came when I disabled X-Cache extension!  After disabling X-Cache my script WORKS!

At first to test I just removed all the content of the xcache module/extension. Mine was located in:

/etc/php5/conf.d/20-xcache.ini

(I emptied the file) then executed:

service php5-fpm restart


Evidently there was some kind of incompatibility or issue which happened with some other things being upgraded overtime. So I decided to just remove X-Cache all together using this command:

apt-get remove php5-xcache

service php5-fpm restart


Now all my problems have been resolved and I am happy this issue is solved!

Initial steps to properly setup Ubuntu Server

Every time I deploy a new ubuntu server for some kind of web development project I always have a list of commands I have to execute to prepare the server. These are what I call initial preparation for ubuntu server. The purpose for these initial setup commands to make sure we have the latest updates, set locale settings and setup security logins.

Here are my list of commands for ubuntu initial setup (grouped by purpose)

Group 1 - Initial Updates

apt-get update
apt-get upgrade
apt-get install build-essential
apt-get install curl

Group 2 - Set Local Settings (language and time zone)

locale-gen en_US en_US.UTF-8
dpkg-reconfigure locales
dpkg-reconfigure tzdata

Group 3 - Setup Security and Login

ssh-keygen -t rsa
nano ~/.ssh/authorized_keys

(optional) - to support PPA and Python

apt-get install software-properties-common 

As you can see... the commands above WILL NOT install any specific server functionality. But it will setup a solid base for you to start building whatever server you need.