Below are some steps to roughly test an atomic host from Project Atomic.
First step is to start an atomic host using any method/cloud provider you like. For me I decided to use openstack since I have Juno running on F21 here in my apartment. I used this user-data for the atomic host:
#cloud-config
password: passw0rd
chpasswd: { expire: False }
ssh_pwauth: True
runcmd:
- [ sh, -c, 'echo -e "ROOT_SIZE=4G\nDATA_SIZE=10G" > /etc/sysconfig/docker-storage-setup']
Note that the build of atomic I used for this testing resides here
docker-storage-setup is a service that can be used to configure the storage configuration for docker in different ways on instance bringup. Notice in the user-data above that I decided to set config variables for docker-storage-setup. They basically mean that I want to resize my atomicos/root LV to 4G and I want to create an atomicos/docker-data LV and make it 10G in size.
To verify the storage was set up successfully, log in (as the fedora user) and become root (usind sudo su -). Now you can check if docker-storage-setup worked by checking the logs as well as looking at the output from lsblk:
# journalctl -o cat --unit docker-storage-setup.service CHANGED: partition=2 start=411648 old: size=12171264 end=12582912 new: size=41531232,end=41942880 Physical volume "/dev/vda2" changed 1 physical volume(s) resized / 0 physical volume(s) not resized Size of logical volume atomicos/root changed from 1.95 GiB (500 extents) to 4.00 GiB (1024 extents). Logical volume root successfully resized Rounding up size to full physical extent 24.00 MiB Logical volume "docker-meta" created Logical volume "docker-data" created # # lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT vda 252:0 0 20G 0 disk ├─vda1 252:1 0 200M 0 part /boot └─vda2 252:2 0 19.8G 0 part ├─atomicos-root 253:0 0 4G 0 lvm /sysroot ├─atomicos-docker--meta 253:1 0 24M 0 lvm └─atomicos-docker--data 253:2 0 10G 0 lvm
To verify Docker runs fine on the atomic host we will perform a simple run of the busybox docker image. This will contact the docker hub, pull down the image, and run /bin/true:
# docker run -it --rm busybox true && echo "PASS" || echo "FAIL" Unable to find image 'busybox' locally Pulling repository busybox e72ac664f4f0: Download complete 511136ea3c5a: Download complete df7546f9f060: Download complete e433a6c5b276: Download complete PASS
After the Docker daemon has started the LVs that were created by docker-storage-setup will be used by device mapper as shown in the lsblk output below:
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda 252:0 0 20G 0 disk
├─vda1 252:1 0 200M 0 part /boot
└─vda2 252:2 0 19.8G 0 part
├─atomicos-root 253:0 0 4G 0 lvm /sysroot
├─atomicos-docker--meta 253:1 0 24M 0 lvm
│ └─docker-253:0-6298462-pool 253:3 0 10G 0 dm
│ └─docker-253:0-6298462-base 253:4 0 10G 0 dm
└─atomicos-docker--data 253:2 0 10G 0 lvm
└─docker-253:0-6298462-pool 253:3 0 10G 0 dm
└─docker-253:0-6298462-base 253:4 0 10G 0 dm
Now on to an atomic upgrade. First let's check what commit we are currently at and store a file in /etc/file1 to save it for us:
# rpm-ostree status
TIMESTAMP (UTC) ID OSNAME REFSPEC
* 2014-11-12 22:28:04 1877f1fa64 fedora-atomic-host fedora-atomic:fedora-atomic/f21/x86_64/docker-host
#
# ostree admin status
* fedora-atomic-host 1877f1fa64be8bec8adcd43de6bd4b5c39849ec7842c07a6d4c2c2033651cd84.0
origin refspec: fedora-atomic:fedora-atomic/f21/x86_64/docker-host
#
# cat /ostree/repo/refs/heads/ostree/0/1/0
1877f1fa64be8bec8adcd43de6bd4b5c39849ec7842c07a6d4c2c2033651cd84
#
# cat /ostree/repo/refs/heads/ostree/0/1/0 > /etc/file1
Now run an upgrade to the latest atomic compose:
# rpm-ostree upgrade Updating from: fedora-atomic:fedora-atomic/f21/x86_64/docker-host 14 metadata, 19 content objects fetched; 33027 KiB transferred in 16 seconds Copying /etc changes: 26 modified, 4 removed, 39 added Transaction complete; bootconfig swap: yes deployment count change: 1) Updates prepared for next boot; run "systemctl reboot" to start a reboot
And do a bit of poking around right before we reboot:
# rpm-ostree status
TIMESTAMP (UTC) ID OSNAME REFSPEC
2014-11-13 10:52:06 18e02c4166 fedora-atomic-host fedora-atomic:fedora-atomic/f21/x86_64/docker-host
* 2014-11-12 22:28:04 1877f1fa64 fedora-atomic-host fedora-atomic:fedora-atomic/f21/x86_64/docker-host
#
# ostree admin status
fedora-atomic-host 18e02c41666ef5f426bc43d01c4ce1b7ffc0611e993876cf332600e2ad8aa7c0.0
origin refspec: fedora-atomic:fedora-atomic/f21/x86_64/docker-host
* fedora-atomic-host 1877f1fa64be8bec8adcd43de6bd4b5c39849ec7842c07a6d4c2c2033651cd84.0
origin refspec: fedora-atomic:fedora-atomic/f21/x86_64/docker-host
#
# reboot
Note
The * in the above output indicates which tree is currently booted.
After reboot now the new tree should be booted. Let's check things out and make /etc/file2 with our new commit hash in it:
# rpm-ostree status
TIMESTAMP (UTC) ID OSNAME REFSPEC
* 2014-11-13 10:52:06 18e02c4166 fedora-atomic-host fedora-atomic:fedora-atomic/f21/x86_64/docker-host
2014-11-12 22:28:04 1877f1fa64 fedora-atomic-host fedora-atomic:fedora-atomic/f21/x86_64/docker-host
#
# ostree admin status
* fedora-atomic-host 18e02c41666ef5f426bc43d01c4ce1b7ffc0611e993876cf332600e2ad8aa7c0.0
origin refspec: fedora-atomic:fedora-atomic/f21/x86_64/docker-host
fedora-atomic-host 1877f1fa64be8bec8adcd43de6bd4b5c39849ec7842c07a6d4c2c2033651cd84.0
origin refspec: fedora-atomic:fedora-atomic/f21/x86_64/docker-host
#
# cat /ostree/repo/refs/heads/ostree/1/1/0
18e02c41666ef5f426bc43d01c4ce1b7ffc0611e993876cf332600e2ad8aa7c0
#
# cat /ostree/repo/refs/heads/ostree/1/1/0 > /etc/file2
As one final item let's boot up a docker container to make sure things still work there:
# docker run -it --rm busybox true && echo "PASS" || echo "FAIL" PASS
Atomic host provides the ability to revert to the previous working tree if things go awry with the new tree. Lets revert our upgrade now and make sure things still work:
# rpm-ostree rollback Moving '1877f1fa64be8bec8adcd43de6bd4b5c39849ec7842c07a6d4c2c2033651cd84.0' to be first deployment Transaction complete; bootconfig swap: yes deployment count change: 0) Sucessfully reset deployment order; run "systemctl reboot" to start a reboot # # rpm-ostree status TIMESTAMP (UTC) ID OSNAME REFSPEC 2014-11-12 22:28:04 1877f1fa64 fedora-atomic-host fedora-atomic:fedora-atomic/f21/x86_64/docker-host * 2014-11-13 10:52:06 18e02c4166 fedora-atomic-host fedora-atomic:fedora-atomic/f21/x86_64/docker-host # # reboot
After reboot:
# rpm-ostree status TIMESTAMP (UTC) ID OSNAME REFSPEC * 2014-11-12 22:28:04 1877f1fa64 fedora-atomic-host fedora-atomic:fedora-atomic/f21/x86_64/docker-host 2014-11-13 10:52:06 18e02c4166 fedora-atomic-host fedora-atomic:fedora-atomic/f21/x86_64/docker-host # # cat /etc/file1 1877f1fa64be8bec8adcd43de6bd4b5c39849ec7842c07a6d4c2c2033651cd84 # cat /etc/file2 cat: /etc/file2: No such file or directory
Notice that /etc/file2 did not exist until after the upgrade so it did not persist during the rollback.
And the final item on the list is to make sure Docker still works:
# docker run -it --rm busybox true && echo "PASS" || echo "FAIL" PASS
Anddd Boom.. You have just put atomic through some paces.
A Fedora 21 Workstation with a huge /var and Virtual Machine Manager / qemu-kvm ... can I just make the qcow2 image bigger with some kind of qemu-img shenanigans?