Originally posted on IBM Developer blog “Exploring PureApplication System, Software Service and more” by Jonathan Deberdt on 31 May 2016 (10073 visits)
Virtual images are the base component of every virtual machine. On IBM PureApplication System (Intel-based) and Service, IBM provides some virtual images called “IBM OS Image for Red Hat Linux Systems”. In your catalog, you can also have virtual images coming from Hypervisor Editions of IBM products or some other virtual images that you have imported, cloned or customized. These virtual images have a defined disk space available but sometimes you need more. To get a larger disk space you can use add-ons in your patterns or increase the disk space within the virtual image.
Unfortunately, increasing the disk space of a virtual image is not straightforward and we will explain here how to do this.
Note: The method described here creates a new partition. Another method is to resize an existing partition, this method is described in my first comment on this article.
1. Creating a new image with a larger disk
First step is to create a new image with a larger disk. The easiest way to do this is to clone an existing image from the catalog.
Once logged in the PureApplication administrative console, go to Catalog -> Virtual Images.
Select the image you want to start with and click the Clone button.
Tip: this virtual image will be a temporary one. We will create the final one later. That’s why I set the version number to 0.9 in this step and the final is tagged as v1.0 in the next step. Choose carefully the name and version number of the virtual images you’ll create. Using an existing name for the virtual image but a different version number can be useful if you already have patterns that use this image : you then can change the image in your pattern by selecting the right version number instead of having to rebuild your pattern.
This will open a popup window. Fill the General information section and click on the Hardware configuration link to change the size of the virtual disk. Here we will increase from 12GB to 40GB.
Click OK. It takes a few minutes to create the new image.
2. Enlarging the file system
Unfortunately, changing the hardware configuration is not sufficient… You need a few steps to make this larger disk available for files. In order to make these steps persistent, we will use the “extend and capture” feature of PureApplication.
We need to:
- extend the image
- connect to the deployed image and choose where we want to add space
- create a new partition
- create a new physical volume
- extend the volume group
- extend the logical volume
- resize the file system
- capture the modified image
2.1 Extend the image
Select the new image you have created in previous step and click the Extend button.
This will create a Classic Virtual System pattern with your virtual image and deploy it once.
Fill the General information section and Deployment configuration section. The requested password is for root user.
After a few minutes, the status of the extended image is set to Draft and the image is deployed as you can see in line In the cloud now. Click on this link to view the deployed instance.
On the instance page, expand the Virtual machines section to get the IP address or hostname of your VM (line Network interface 1 in the Hardware and network sub-section).
2.2 Connect to the deployed image and choose where we want to add space
Connect through SSH to the virtual machine. You can use the Log In link provided by the PureApplication console (see screenshot above) or a tool such as PuTTY on Windows or a Terminal on Linux or MacOS. Log as root with the password you have provided in the deployment configuration.
Type fdisk -l to list the current disk partitions.
-bash-4.1# fdisk -l Disk /dev/sda: 42.9 GB, 42949672960 bytes 255 heads, 63 sectors/track, 5221 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000738bb Device Boot Start End Blocks Id System /dev/sda1 * 1 32 256000 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 32 1567 12325888 8e Linux LVM Disk /dev/mapper/vg_root-LogVol01: 2147 MB, 2147483648 bytes 255 heads, 63 sectors/track, 261 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/mapper/vg_root-LogVol00: 10.5 GB, 10473177088 bytes 255 heads, 63 sectors/track, 1273 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000
As you can see on first line, the disk /dev/sda is 42.9 GB large but only 2147 MB and 10.5 GB are used by /dev/mapper/vg_root-LogVol01 and /dev/mapper/vg_root-LogVol00 respectively.
The only physical disk is called /dev/sda and contains 2 partitions: /dev/sda1 and /dev/sda2.
Type df -h
-bash-4.1# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_root-LogVol00 9.5G 2.4G 6.7G 26% / tmpfs 1000M 0 1000M 0% /dev/shm /dev/sda1 239M 55M 172M 24% /boot
This gives you the available file system space. As you can see, /dev/mapper/vg_root-LogVol00 is mounted on /. We will extend /dev/mapper/vg_root-LogVol00 as much as possible to get more space on /.
2.3 Create a new partition
We will create a new partition on device /dev/sda.
Type fdisk /dev/sda.
-bash-4.1# fdisk /dev/sda WARNING: DOS-compatible mode is deprecated. It's strongly recommended to switch off the mode (command 'c') and change display units to sectors (command 'u'). Command (m for help):
Type p to list the partitions.
Command (m for help): p Disk /dev/sda: 42.9 GB, 42949672960 bytes 255 heads, 63 sectors/track, 5221 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000738bb Device Boot Start End Blocks Id System /dev/sda1 * 1 32 256000 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 32 1567 12325888 8e Linux LVM Command (m for help):
Type n to create a new partition. As there are only 2 existing primary partitions, we will create a third primary partition. By default, fdisk proposes to use all the available space (first and last available cylinders). In this example, we will use the default values.
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 3
First cylinder (1567-5221, default 1567):
Using default value 1567
Last cylinder, +cylinders or +size{K,M,G} (1567-5221, default 5221):
Using default value 5221
Command (m for help):
Type p to list the partitions.
Command (m for help): p Disk /dev/sda: 42.9 GB, 42949672960 bytes 255 heads, 63 sectors/track, 5221 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000738bb Device Boot Start End Blocks Id System /dev/sda1 * 1 32 256000 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 32 1567 12325888 8e Linux LVM /dev/sda3 1567 5221 29354770+ 83 Linux Command (m for help):
The new partition, /dev/sda3, is from “Linux” type. Its type ID is 83. We will change it to “Linux LVM”, type ID 8e.
Type t to change the type of our 3rd partition. Then list the partitions once again to check the configuration.
Command (m for help): t Partition number (1-4): 3 Hex code (type L to list codes): 8e Changed system type of partition 3 to 8e (Linux LVM) Command (m for help): p Disk /dev/sda: 42.9 GB, 42949672960 bytes 255 heads, 63 sectors/track, 5221 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000738bb Device Boot Start End Blocks Id System /dev/sda1 * 1 32 256000 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 32 1567 12325888 8e Linux LVM /dev/sda3 1567 5221 29354770+ 8e Linux LVM Command (m for help):
Type w to write the changes in the partition table.
Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. WARNING: Re-reading the partition table failed with error 16: Device or resource busy. The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or kpartx(8) Syncing disks.
To be taken into account, the system needs to be restarted. You can use the reboot command.
2.4 Create a new physical volume
Once the virtual machine is rebooted, connect to it through SSH. You can check the current partition table using fdisk -l.
-bash-4.1# fdisk -l Disk /dev/sda: 42.9 GB, 42949672960 bytes 255 heads, 63 sectors/track, 5221 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000738bb Device Boot Start End Blocks Id System /dev/sda1 * 1 32 256000 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 32 1567 12325888 8e Linux LVM /dev/sda3 1567 5221 29354770+ 8e Linux LVM Disk /dev/mapper/vg_root-LogVol01: 2147 MB, 2147483648 bytes 255 heads, 63 sectors/track, 261 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/mapper/vg_root-LogVol00: 10.5 GB, 10473177088 bytes 255 heads, 63 sectors/track, 1273 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000
Create the physical volume on the new partition using pvcreate:
-bash-4.1# pvcreate /dev/sda3 Physical volume "/dev/sda3" successfully created
2.5 Extend the volume group
We will now get the name of the volume group using the vgdisplay command:
-bash-4.1# vgdisplay --- Volume group --- VG Name vg_root System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 3 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 2 Max PV 0 Cur PV 1 Act PV 1 VG Size 11.75 GiB PE Size 4.00 MiB Total PE 3009 Alloc PE / Size 3009 / 11.75 GiB Free PE / Size 0 / 0 VG UUID Vwenuf-OdXe-Ojtm-XWMo-XVQQ-o0L7-2q3jzA
Extend the volume group (here vg_root) to the new partition with vgextend:
-bash-4.1# vgextend vg_root /dev/sda3 Volume group "vg_root" successfully extended
You can check the new detailed volume group information using vgdisplay -v:
-bash-4.1# vgdisplay -v Using volume group(s) on command line. Finding all volume groups. --- Volume group --- VG Name vg_root System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 4 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 2 Max PV 0 Cur PV 2 Act PV 2 VG Size 39.75 GiB PE Size 4.00 MiB Total PE 10175 Alloc PE / Size 3009 / 11.75 GiB Free PE / Size 7166 / 27.99 GiB VG UUID Vwenuf-OdXe-Ojtm-XWMo-XVQQ-o0L7-2q3jzA --- Logical volume --- LV Path /dev/vg_root/LogVol01 LV Name LogVol01 VG Name vg_root LV UUID scPXkX-K6ue-jhyn-sbll-LzZj-C1fb-R8ejTG LV Write Access read/write LV Creation host, time icon-vm-068-230.rtp.raleigh.ibm.com, 2014-02-07 15:55:35 +0000 LV Status available # open 1 LV Size 2.00 GiB Current LE 512 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:0 --- Logical volume --- LV Path /dev/vg_root/LogVol00 LV Name LogVol00 VG Name vg_root LV UUID 8bl26C-VZOh-elAN-X4RN-DDz1-3znH-ibaieB LV Write Access read/write LV Creation host, time icon-vm-068-230.rtp.raleigh.ibm.com, 2014-02-07 15:55:35 +0000 LV Status available # open 1 LV Size 9.75 GiB Current LE 2497 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:1 --- Physical volumes --- PV Name /dev/sda2 PV UUID WwgsZI-MmOt-IDVn-iJgr-Pevc-mNIL-eb4SZI PV Status allocatable Total PE / Free PE 3009 / 0 PV Name /dev/sda3 PV UUID I8OMac-EooX-kW9B-Y3Zq-XRVG-FIbz-gTIRI9 PV Status allocatable Total PE / Free PE 7166 / 7166
As you can see in the last lines, the physical volume /dev/sda3 is now part of the volume group and is free (Free PE : 7166).
2.6 Extend the logical volume
The tool to extend the mapped logical volume /dev/mapper/vg_root-LogVol00 is lvextend.
Type lvextend -l +100%FREE /dev/mapper/vg_root-LogVol00. This will extend the /dev/mapper/vg_root-LogVol00 with all available space.
-bash-4.1# lvextend -l +100%FREE /dev/vg_root/LogVol00 Size of logical volume vg_root/LogVol00 changed from 9.75 GiB (2497 extents) to 37.75 GiB (9663 extents). Logical volume LogVol00 successfully resized
2.7 Resize the file system
Next step is to resize the file system to use the newly available space. Use the resize2fs command on the logical volume.
-bash-4.1# resize2fs /dev/vg_root/LogVol00 resize2fs 1.41.12 (17-May-2010) Filesystem at /dev/vg_root/LogVol00 is mounted on /; on-line resizing required old desc_blocks = 1, new_desc_blocks = 3 Performing an on-line resize of /dev/vg_root/LogVol00 to 9894912 (4k) blocks. The filesystem on /dev/vg_root/LogVol00 is now 9894912 blocks long.
Check the partitions with fdisk -l.
-bash-4.1# fdisk -l Disk /dev/sda: 42.9 GB, 42949672960 bytes 255 heads, 63 sectors/track, 5221 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000738bb Device Boot Start End Blocks Id System /dev/sda1 * 1 32 256000 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 32 1567 12325888 8e Linux LVM /dev/sda3 1567 5221 29354770+ 8e Linux LVM Disk /dev/mapper/vg_root-LogVol01: 2147 MB, 2147483648 bytes 255 heads, 63 sectors/track, 261 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/mapper/vg_root-LogVol00: 40.5 GB, 40529559552 bytes 255 heads, 63 sectors/track, 4927 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000
As you can see, /dev/mapper/vg_root-LogVol00 is now 40.5 GB large.
You can also use df -h to see available space:
-bash-4.1# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_root-LogVol00 38G 2.4G 33G 7% / tmpfs 1000M 0 1000M 0% /dev/shm /dev/sda1 239M 55M 172M 24% /boot
2.8 Capture the modified image
Now that the deployed virtual image has been modified, we will use PureApplication capability to record these changes using the Capture function. Go back to the PureApplication administrative console and the virtual image you have extended. Click the Capture button then OK to confirm.
Now that the image has been captured, you can test it by creating a simple pattern with this image and check if this new image meets your requirements for disk space using for example the df -h command.
3. Final steps
If you need more customisation of your virtual image, you can make additional changes and recapture it.
Otherwise, it is advised to lock it so that the image will be in read-only mode. New changes to this image will require to clone or extend it.
Your virtual image is now ready to be used in your patterns.
The last steps are just cleanup. You can delete:
- The classic virtual system instance and pattern that PureApplication has created for extend and capture. It has the name of your virtual image (see links “In the cloud now” and “Included in patterns” in your virtual image).
- The temporary virtual image created at first step (cloned image).
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