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How to add a new storage volume to Linux VM locally and on AWS EC2.

Sooner or later we all run out of space. Today I am going to demo how to add a new
storage to Linux VM. First we will look at how to do this on local VM with virtualbox and vagrant,
then in AWS.

1. Adding a new volume locally.
2. Splitting disk into partitions
3. Spinning AWS EC2 instance and adding a new volume manually.
4. Attaching new volume with AWS CLI.

So let’s assume you have vagrant and virtualbox installed, let’s spin up a new VM:

vagrant init ubuntu/trusty64 && vagrant up && vagrant ssh

You can pick up newer version of Ubuntu of course, Xenial or Zesty, or any other Linux distro even, I have ubuntu/trusty64 vagrant box already downloaded, so I will be using that one.

First let’s check what we have already got there with ‘list block devices’ command:

vagrant@sensuclient:~$ lsblk
NAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda      8:0    0  40G  0 disk
`-sda1   8:1    0  40G  0 part /
vagrant@sensuclient:~$

Now let’s exit VM and stop it:


vagrant halt
==> sensuclient: Attempting graceful shutdown of VM...

Then we need to go to virtualbox and add new disk as shown below:

Once it is done, we can start VM and check devices again:

vagrant up  && vagrant ssh  

vagrant@sensuclient:~$ sudo lsblk -f
NAME   FSTYPE LABEL           MOUNTPOINT
sda
`-sda1 ext4   cloudimg-rootfs /
sdb

As you can see new disk, ‘sdb’ has been added to the list.

Next we need to crate a filesystem:


vagrant@sensuclient:~$ sudo mkfs -t ext4 /dev/sdb
mke2fs 1.42.9 (4-Feb-2014)
/dev/sdb is entire device, not just one partition!
Proceed anyway? (y,n) y
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
65808 inodes, 262880 blocks
13144 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=272629760
9 block groups
32768 blocks per group, 32768 fragments per group
7312 inodes per group
Superblock backups stored on blocks:
	32768, 98304, 163840, 229376

Allocating group tables: done
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

Now if we list devices we will see it’s FS type populated:


vagrant@sensuclient:~$ sudo lsblk -f
NAME   FSTYPE LABEL           MOUNTPOINT
sda
`-sda1 ext4   cloudimg-rootfs /
sdb    ext4

Now disk is ready to be mounted:


sudo mkdir /newvolume
sudo mount /dev/sdb /newvolume/

Last thing is to add it to fstab, so when we restart VM disk is still there:


vagrant@sensuclient:~$ sudo cat /etc/fstab
LABEL=cloudimg-rootfs	/	 ext4	defaults	0 0
/dev/sdb   /newvolume  ext4   defaults   0  0

Here is what columns of fstab mean:
1 – device name
2 – mount point
3 – filesystem type
4 – permissions
5 – backup option – 0 is no
6 – fsck scanning – 0 is no

2. Splitting disk into partitions.

Now, let’s split out disk to the partitions using GNU Parted – a partition manipulation program.


vagrant@sensuclient:~$ sudo parted -l
Model: ATA VBOX HARDDISK (scsi)
Disk /dev/sda: 42.9GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type     File system  Flags
 1      1049kB  42.9GB  42.9GB  primary  ext4         boot


Model: ATA VBOX HARDDISK (scsi)
Disk /dev/sdb: 1077MB
Sector size (logical/physical): 512B/512B
Partition Table: loop

Number  Start  End     Size    File system  Flags
 1      0.00B  1077MB  1077MB  ext4

We can use device ids or names, let’s use ids, first we need to find it:


vagrant@sensuclient:~$ file  /dev/disk/by-id/*
/dev/disk/by-id/ata-VBOX_HARDDISK_VB652794d8-c5261a54:       symbolic link to `../../sdb'
/dev/disk/by-id/ata-VBOX_HARDDISK_VB685622b2-c8a29bf2:       symbolic link to `../../sda'
/dev/disk/by-id/ata-VBOX_HARDDISK_VB685622b2-c8a29bf2-part1: symbolic link to `../../sda1'

It is ‘/dev/disk/by-id/ata-VBOX_HARDDISK_VB652794d8-c5261a54’ for or newly added ‘sdb’ disk.

First thing we will do is label it with partition type, we are going to use GUID Partition Table (GPT):


vagrant@sensuclient:~$ sudo parted /dev/disk/by-id/ata-VBOX_HARDDISK_VB652794d8-c5261a54 mklabel gpt
Warning: The existing disk label on /dev/sdb will be destroyed and all data on this disk will be lost. Do you want to continue?
Yes/No? yes

Now let’s split into two parts:


vagrant@sensuclient:~$ sudo parted -a opt /dev/disk/by-id/ata-VBOX_HARDDISK_VB652794d8-c5261a54 mkpart primary 0% 50%
Information: You may need to update /etc/fstab.

vagrant@sensuclient:~$ sudo parted -a opt /dev/disk/by-id/ata-VBOX_HARDDISK_VB652794d8-c5261a54 mkpart primary  50% 100%
Information: You may need to update /etc/fstab.

You can delete if something went wrong, in the example above I named both primary, let’s fix it:


vagrant@sensuclient:~$ sudo parted -a opt /dev/disk/by-id/ata-VBOX_HARDDISK_VB652794d8-c5261a54 rm 1
vagrant@sensuclient:~$ sudo parted -a opt /dev/disk/by-id/ata-VBOX_HARDDISK_VB652794d8-c5261a54 rm 2

And split again:




vagrant@sensuclient:~$ sudo parted -a opt /dev/disk/by-id/ata-VBOX_HARDDISK_VB652794d8-c5261a54 mkpart primary 0% 50%
Information: You may need to update /etc/fstab.

vagrant@sensuclient:~$ sudo parted -a opt /dev/disk/by-id/ata-VBOX_HARDDISK_VB652794d8-c5261a54 mkpart secondary  50% 100%
Information: You may need to update /etc/fstab.

Let's view it agian:


vagrant@sensuclient:~$ sudo parted -l
Model: ATA VBOX HARDDISK (scsi)
Disk /dev/sda: 42.9GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type     File system  Flags
 1      1049kB  42.9GB  42.9GB  primary  ext4         boot


Model: ATA VBOX HARDDISK (scsi)
Disk /dev/sdb: 1077MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size   File system  Name       Flags
 1      1049kB  538MB   537MB               primary
 2      538MB   1076MB  538MB               secondary

We need to create filesystem on each partition next:


vagrant@sensuclient:~$  sudo mkfs -t ext4 /dev/sdb1
mke2fs 1.42.9 (4-Feb-2014)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
32768 inodes, 131072 blocks
6553 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=134217728
4 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
	32768, 98304

Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done


vagrant@sensuclient:~$  sudo mkfs -t ext4 /dev/sdb2
mke2fs 1.42.9 (4-Feb-2014)
warning: 256 blocks unused.

Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
32832 inodes, 131072 blocks
6553 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=134217728
4 block groups
32768 blocks per group, 32768 fragments per group
8208 inodes per group
Superblock backups stored on blocks:
	32768, 98304

Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done

Our partitions are ready:


vagrant@sensuclient:~$ sudo lsblk -f
NAME   FSTYPE LABEL           MOUNTPOINT
sda
`-sda1 ext4   cloudimg-rootfs /
sdb
|-sdb1 ext4
`-sdb2 ext4
vagrant@sensuclient:~$

We now can mount them, but first let's create a mount point directories:


vagrant@sensuclient:~$ sudo mkdir newvol_part1  newvol_part2
vagrant@sensuclient:~$ sudo mount /dev/sdb1 /newvol_part1
vagrant@sensuclient:~$ sudo mount /dev/sdb2 /newvol_part2

And finally test it is working:

vagrant@sensuclient:~$ sudo echo test2 > /newvol_part2/testfile
-bash: /newvol_part2/testfile: Permission denied

Why permission denied, as I am running as sudo? Well, because apart from running echo command,
there is also a redirection involved which is executed by the shell not ran as sudo.
We can fix it either by using 'tee' or running the whole thing as argument to shell executed by sudo:


echo test | sudo tee /newvol_part1/testfile
echo test2 | sudo tee /newvol_part2/testfile
sudo sh -c "echo 'test' > /newvol_part1/testfile2"

I personally prefer 'tee' way.


vagrant@sensuclient:~$ cat /newvol_part*/testfile
test
test2

Test is positive, let's move to AWS now.

3. Spinning AWS EC2 instance and adding a new volume manually.

 

So assuming we have access to AWS console and ssh key pair to connect to it,
we will need to do the next steps:

1. spin up an EC2 instance of type t2 micro and configure security group in a way so that we can connect to port 22 for ssh.
2. connect to it, run lsblk and make sure we only got single disk.
3. go to EBS section and create a volume.
4. attach the volume to our EC2 instance, the cool thing is we can do it while it is running, unlike virtualbox, where we had to stop it.
5. connect to it agian, run lsblk and make sure we can see second disk.

All the steps is demonstrated in the gif below:

So once we done what is listed above, the rest is exactly similar to what we did earlier with Ubuntu on Local VM.

First list partitions:


[ec2-user@ip-172-31-8-44 ~]$ sudo parted -l
Model: Xen Virtual Block Device (xvd)
Disk /dev/xvda: 8590MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system  Name                 Flags
128     1049kB  2097kB  1049kB               BIOS Boot Partition  bios_grub
 1      2097kB  8590MB  8588MB  ext4         Linux


Error: /dev/xvdf: unrecognised disk label

[ec2-user@ip-172-31-8-44 ~]$

Then label it and split into partitions and then list again:


[ec2-user@ip-172-31-8-44 ~]$ sudo parted /dev/xvdf mklabel gpt
Information: You may need to update /etc/fstab.

[ec2-user@ip-172-31-8-44 ~]$ sudo parted -a opt /dev/xvdf  mkpart primary 0% 50%
Information: You may need to update /etc/fstab.

[ec2-user@ip-172-31-8-44 ~]$ sudo parted -a opt /dev/xvdf  mkpart secondary 50% 100%
Information: You may need to update /etc/fstab.

[ec2-user@ip-172-31-8-44 ~]$ sudo parted -l
Model: Xen Virtual Block Device (xvd)
Disk /dev/xvda: 8590MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system  Name                 Flags
128     1049kB  2097kB  1049kB               BIOS Boot Partition  bios_grub
 1      2097kB  8590MB  8588MB  ext4         Linux


Model: Xen Virtual Block Device (xvd)
Disk /dev/xvdf: 1074MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size   File system  Name       Flags
 1      1049kB  537MB   536MB               primary
 2      537MB   1073MB  536MB               secondary

Next install filesystem on partitions:


[ec2-user@ip-172-31-8-44 ~]$  sudo mkfs -t ext4 /dev/xvdf1
mke2fs 1.42.12 (29-Aug-2014)
Creating filesystem with 523264 1k blocks and 131072 inodes
Filesystem UUID: c8ea4c26-ba32-4400-8147-6228ed8a3e3a
Superblock backups stored on blocks:
	8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409

Allocating group tables: done
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

[ec2-user@ip-172-31-8-44 ~]$  sudo mkfs -t ext4 /dev/xvdf2
mke2fs 1.42.12 (29-Aug-2014)
Creating filesystem with 523264 1k blocks and 131072 inodes
Filesystem UUID: e7b2ca1f-f876-4b8f-803f-697a2b8f7d50
Superblock backups stored on blocks:
	8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409

Allocating group tables: done
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

Check our disks:


[ec2-user@ip-172-31-8-44 ~]$ lsblk -f
NAME FSTYPE LABEL UUID MOUNTPOINT
xvda
└─xvda1 ext4 / df24ba12-defa-4725-9a31-2ff9b332ae90 /
xvdf
├─xvdf2 ext4 e7b2ca1f-f876-4b8f-803f-697a2b8f7d50
└─xvdf1 ext4 c8ea4c26-ba32-4400-8147-6228ed8a3e3a
[ec2-user@ip-172-31-8-44 ~]$

And finally mount and test filesystem:


[ec2-user@ip-172-31-8-44 ~]$ sudo mkdir /newvol_part1 /newvol_part2

[ec2-user@ip-172-31-8-44 ~]$  sudo mount /dev/xvdf1 /newvol_part1
[ec2-user@ip-172-31-8-44 ~]$  sudo mount /dev/xvdf2 /newvol_part2

[ec2-user@ip-172-31-8-44 ~]$  echo test | sudo tee /newvol_part1/testfile
test
[ec2-user@ip-172-31-8-44 ~]$  echo test | sudo tee /newvol_part2/testfile
test
[ec2-user@ip-172-31-8-44 ~]$ cat /newvol_part*/testfile
test
test

Finally let's detach the volume, but first unmount file systems:


[ec2-user@ip-172-31-8-44 ~]$ sudo umount /dev/xvdf1
[ec2-user@ip-172-31-8-44 ~]$ sudo umount /dev/xvdf2
[ec2-user@ip-172-31-8-44 ~]$ lsblk
NAME    MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda    202:0    0   8G  0 disk
└─xvda1 202:1    0   8G  0 part /

4. Attaching new volume with AWS CLI.

Now we can detach the volume. Let's look how we can attach volume with AWS cli now:


[ec2-user@ip-172-31-8-44 ~]$ aws ec2 attach-volume \
  --volume-id vol-0c0677b3d644f0f0d \
  --instance-id i-0f9063a259cec8f08  \
  --device /dev/xvdf
 
 You must specify a region. You can also configure your region by running "aws configure".

Oh, didn't quite work, let's configure it:


[ec2-user@ip-172-31-8-44 ~]$ aws configure
AWS Access Key ID [****************]:
AWS Secret Access Key [****************]:
Default region name [None]: eu-west-2
Default output format [None]:

And now try again:


[ec2-user@ip-172-31-8-44 ~]$ aws ec2 attach-volume \
  --volume-id vol-0c0677b3d644f0f0d \
  --instance-id i-0f9063a259cec8f08 \
  --device /dev/xvdf
{
    "AttachTime": "2017-12-02T16:37:26.855Z",
    "InstanceId": "i-0f9063a259cec8f08",
    "VolumeId": "vol-0c0677b3d644f0f0d",
    "State": "attaching",
    "Device": "/dev/xvdf"
}

[ec2-user@ip-172-31-8-44 ~]$ lsblk
NAME    MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda    202:0    0   8G  0 disk
└─xvda1 202:1    0   8G  0 part /
xvdf    202:80   0   1G  0 disk
[ec2-user@ip-172-31-8-44 ~]$

That is it, next time I hope to get my hands dirty with LVM.