AWS: Free tier t2.micro 2 instance A and B
OS: RHEL 6.6
root FS: Ext4
Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 5.8G 4.1G 1.5G 74% /
Using: AWS CLI (They can be done easily from aws console with web ui)
Task: Root file system of instance B from 6G to available space.
Disclaimer: Please be careful while performing these steps as they are too risk and can cause loss of entire system.
Steps:
- Stop the instance B #aws ec2 stop-instances –instance-ids <instance B ID>
- Detach the root volume from instance B #aws ec2 detach-volume –volume-id=”vol-xxxxxxxxx”
- Create snashot (For recovery in case you last the file system while doing below steps) $aws ec2 create-snapshot –volume-id “vol-xxxxxxxxx” –description “instance B root vol backup”
–Note: This is an extremly important to create snapshot for the safety to recover
- Attach to Instance A #aws ec2 attach-volume –volume-id=”vol-0d61acbe3bff8d115″ –instance-id=”i-05c133fd050dbd04d” –device=”/dev/sdf”
- Connect to the instance A through ssh $ssh -i “mykey.pem” ec2-user@<public ip of instanc A>
- Use command “lsblk” to verify the list of devices $sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 10G 0 disk
└─xvda1 202:1 0 6G 0 part /
xvdb 202:16 0 10G 0 disk /hadoop
xvdf 202:80 0 30G 0 disk
└─xvdf1 202:81 0 6G 0 part
- Using parted, recreated the 6G partition xvdf1 to 10G $sudo parted /dev/xvdf
- Change units to sectors (parted) unit s
- Print the current partion
(parted) print
Model: Xen Virtual Block Device (xvd)
Disk /dev/xvdf: 62914560s
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Number Start End Size File system Name Flags
1 2048s 12584959s 12582912s ext4 ext4 boot
- Delete the partion (parted) rm 1
- Create new partition (parted) mkpart ext4 2048s 100% Warning: You requested a partition from 2048s to 62914559s. The closest location we can manage is 2048s to 20971486s.Is this still acceptable to you?Yes/No? Yes
- Print New Partition and verify(parted) print
Model: Xen Virtual Block Device (xvd)
Disk /dev/xvdf: 62914560s
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Number Start End Size File system Name Flags
1 2048s 20971486s 20969439s ext4 ext4
- Make it bootable (parted) set 1 boot on
- Quit from parted (parted) quit
- Run e2fsck $sudo e2fsck -f /dev/xvdf1
e2fsck 1.41.12 (17-May-2010)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/xvdf1: 58700/393216 files (0.1% non-contiguous), 631205/1572864 blocks
- Extend using resize2fs command $sudo resize2fs /dev/xvdf1
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/xvdf1 to 2621179 (4k) blocks.
The filesystem on /dev/xvdf1 is now 2621179 blocks long.
- Verify attaching the extended partition $sudo mount -t ext4 /dev/xvdf1 /mnt
- Verify the file system with ls and $sudo df -h /mnt
Filesystem Size Used Avail Use% Mounted on
/dev/xvdf1 9.8G 2.2G 7.1G 24% /mnt
Now detach the ebs volume from instance A and attach it to instance B as root device i.e. “/dev/sda”
16. aws ec2 detach-volume –volume-id=”vol-*********”
17. aws ec2 attach-volume –volume-id=”vol-*********” –instance-id=”Instance B id” –device=”/dev/sda1“
Note: attaching device as /dev/sda1 is import, as aws treats that as root device.
18. Start the instance B
aws ec2 start-instances –instance-id=”Instance B id”
19. Connect to the instance B through ssh and check file system size.
$ssh -i “mykey.pem” ec2-user@<public ip of instanc B>
df -h
Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 9.8G 2.2G 7.1G 24% /
tmpfs 498M 0 498M 0% /dev/shm
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