2019-08-20 ebs-grow

1 minute read

need moar ebs

AWS EBS volumes. Yes I know that everything in AWS should be immutable and disposable. But sometimes they aren’t. We don’t need to go into the philosophical rammifcations of that what we need is a fix. First we find the instance, then the volume, then we grow the volume in aws, then we grow the volume on the box

Lets go and describe the instance

$ aws ec2 describe-instances --filters Name=tag:Name,Values='MyMagicServer' | jq '.Reservations[].Instances' |jq 'map({
    id:   .InstanceId,
    ip:   (.PrivateIpAddress // "<terminated>"),
    enis: [.NetworkInterfaces[].PrivateIpAddress],
    devicename: [.BlockDeviceMappings[].DeviceName],
    VolumeId: [.BlockDeviceMappings[].Ebs.VolumeId],
    tags: (.Tags // [] | map({ key: .Key, value: .Value }) | from_entries)
  })'


  [
  {
    "id": "i-not-a-real-id",
    "ip": "1.1.5.5.",
    "enis": [
      "1.1.5.5"
    ],
    "devicename": [
      "/dev/xvda"
    ],
    "VolumeId": [
      "vol-0notarealvolume"
      
    ],
    "tags": {
      "Name": "MyMagicServer"
    }
  }
]

great now we have the volumeId so lets see how big it is

$ aws ec2 describe-volumes \
    --region us-east-1 \
    --filters Name=attachment.instance-id,Values=i-0notarealvolume | jq '.Volumes'| jq 'map({
    volumeId:   .VolumeId,
    size:   .Size 
  })'

[
  {
    "volumeId": "vol-0notarealvolume",
    "size": 100
  } 
]

Next we will make the volume bigger

$ aws ec2 --region us-east-1 modify-volume --size 1024 --volume-id vol-0enotarealvolume

{
    "VolumeModification": {
        "TargetIops": 3072,
        "TargetSize": 1024,
        "Progress": 0,
        "ModificationState": "modifying",
        "StartTime": "2019-08-20T18:42:21.000Z",
        "TargetVolumeType": "gp2",
        "OriginalVolumeType": "gp2",
        "OriginalSize": 100,
        "VolumeId": "vol-0enotarealvolume",
        "OriginalIops": 300
    }
}

Next we will need to go to the box and grow the volume

ssh in to the box verify the size

$ ssh ec2-user@1.1.5.5
$ sudo su 

[root@ip-1-1-5-5 ec2-user]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1       99G   21G   78G  22% /
devtmpfs         15G   60K   15G   1% /dev
tmpfs            15G     0   15G   0% /dev/shm

issue the command growpart /dev/xvda 1

[root@ip-1-1-5-5 ec2-user]# growpart /dev/xvda 1
CHANGED: disk=/dev/xvda partition=1: start=4096 old: size=209711070,end=209715166 new: size=2147479518,end=2147483614

issue the command resize2fs /dev/xvda1

[root@ip-1-1-5-5 ec2-user]# resize2fs /dev/xvda1
resize2fs 1.42.12 (29-Aug-2014)
Filesystem at /dev/xvda1 is mounted on /; on-line resizing required
old_desc_blocks = 7, new_desc_blocks = 64
The filesystem on /dev/xvda1 is now 268434939 (4k) blocks long.

verify the size

[root@ip-1-1-5-5 ec2-user]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1     1008G   21G  987G   3% /
devtmpfs         15G   60K   15G   1% /dev
tmpfs            15G     0   15G   0% /dev/shm

profit

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