Friday, 20 August 2021

Kata Containers - Building a Pod Sandbox image and QEMU says "No No No"

 As ever, I'm tinkering with Kata 2.0, currently helping a friend build the Pod Sandbox image using the Image Builder tool.

Specifically, the command: -

~/go/src/github.com/kata-containers/kata-containers/tools/osbuilder/image-builder/image_builder.sh ~/fedora_rootfs

fails with: -

...
losetup: /tmp/tmp.bHz11oY851: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
ERROR: File /dev/loop0p1 is not a block device
losetup: /tmp/tmp.bHz11oY851: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
ERROR: File /dev/loop1p1 is not a block device
losetup: /tmp/tmp.bHz11oY851: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
ERROR: File /dev/loop9p1 is not a block device
losetup: /tmp/tmp.bHz11oY851: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
ERROR: File /dev/loop10p1 is not a block device
losetup: /tmp/tmp.bHz11oY851: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
ERROR: File /dev/loop11p1 is not a block device
...
ERROR: File /dev/loop86p1 is not a block device
ERROR: Could not calculate the required disk size
INFO: Creating raw disk with size 126M
/root/go/src/github.com/kata-containers/kata-containers/tools/osbuilder/image-builder/image_builder.sh: line 362: qemu-img: command not found

The solution is kinda in the error - we're missing qemu-img which is easily installed: -

apt-get update && apt-get install -y qemu-utils

Hit:1 https://download.docker.com/linux/ubuntu focal InRelease
Hit:2 http://us.archive.ubuntu.com/ubuntu focal InRelease
Get:3 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
Get:4 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease [101 kB]
Get:5 http://us.archive.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Fetched 328 kB in 1s (273 kB/s)   
Reading package lists... Done
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  linux-headers-5.4.0-72 linux-headers-5.4.0-72-generic linux-image-5.4.0-72-generic linux-modules-5.4.0-72-generic linux-modules-extra-5.4.0-72-generic
Use 'apt autoremove' to remove them.
The following additional packages will be installed:
  libiscsi7 qemu-block-extra sharutils
Suggested packages:
  debootstrap sharutils-doc bsd-mailx | mailx
The following NEW packages will be installed:
  libiscsi7 qemu-block-extra qemu-utils sharutils
0 upgraded, 4 newly installed, 0 to remove and 0 not upgraded.
Need to get 1,246 kB of archives.
After this operation, 7,247 kB of additional disk space will be used.
Get:1 http://us.archive.ubuntu.com/ubuntu focal/main amd64 libiscsi7 amd64 1.18.0-2 [63.9 kB]
Get:2 http://us.archive.ubuntu.com/ubuntu focal-updates/main amd64 qemu-block-extra amd64 1:4.2-3ubuntu6.17 [54.4 kB]
Get:3 http://us.archive.ubuntu.com/ubuntu focal-updates/main amd64 qemu-utils amd64 1:4.2-3ubuntu6.17 [973 kB]
Get:4 http://us.archive.ubuntu.com/ubuntu focal/main amd64 sharutils amd64 1:4.15.2-4build1 [155 kB]
Fetched 1,246 kB in 1s (1,273 kB/s)
Selecting previously unselected package libiscsi7:amd64.
(Reading database ... 157815 files and directories currently installed.)
Preparing to unpack .../libiscsi7_1.18.0-2_amd64.deb ...
Unpacking libiscsi7:amd64 (1.18.0-2) ...
Selecting previously unselected package qemu-block-extra:amd64.
Preparing to unpack .../qemu-block-extra_1%3a4.2-3ubuntu6.17_amd64.deb ...
Unpacking qemu-block-extra:amd64 (1:4.2-3ubuntu6.17) ...
Selecting previously unselected package qemu-utils.
Preparing to unpack .../qemu-utils_1%3a4.2-3ubuntu6.17_amd64.deb ...
Unpacking qemu-utils (1:4.2-3ubuntu6.17) ...
Selecting previously unselected package sharutils.
Preparing to unpack .../sharutils_1%3a4.15.2-4build1_amd64.deb ...
Unpacking sharutils (1:4.15.2-4build1) ...
Setting up sharutils (1:4.15.2-4build1) ...
Setting up libiscsi7:amd64 (1.18.0-2) ...
Setting up qemu-block-extra:amd64 (1:4.2-3ubuntu6.17) ...
Setting up qemu-utils (1:4.2-3ubuntu6.17) ...
Processing triggers for libc-bin (2.31-0ubuntu9.2) ...
Processing triggers for man-db (2.9.1-1) ...
Processing triggers for install-info (6.7.0.dfsg.2-5) ...

and validated: -

which qemu-img

/usr/bin/qemu-img

Actually, the Kata documentation does cover this: -


If you do not wish to build under Docker, remove the USE_DOCKER variable in the previous command and ensure the qemu-img command is available on your system.

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