Boot Environments
Boot environments in solaris 11 are multiple images with different kernel, software applications and packages. Only one boot environment can be active at a time. We can boot into different boot environments according to our need. The command to manage boot environments in solaris is beadm. BEs are extremely useful in case of rolling back any software upgrades. The BEs are actually designed over ZFS file system, so its important to have ZFS file system for root.
Now by default we have a BE with name solaris when you install a fresh solaris 11 operating system.
# beadm list BE Active Mountpoint Space Policy Created -- ------ ---------- ----- ------ ------- solaris NR / 2.28G static 2013-11-19 02:41
As you can see the default BE solaris is the active BE on reboot (NR flag denotes Active on next reboot).
Let us now create a new boot environment called geekBE.
# beadm create geekBE
# beadm list BE Active Mountpoint Space Policy Created -- ------ ---------- ----- ------ ------- geekBE - - 150.0K static 2013-11-19 10:19 solaris NR / 2.28G static 2013-11-19 02:41
As you can see the new BE is created but its not active. Check the size of this BE, 150 KB. Check the size of the geekBE when you activate it.
To activate the new BE :
The geekBE will get activated on next reboot. As you can see in the Active column below (R denotes reboot)
# beadm activate geekBE
# beadm list BE Active Mountpoint Space Policy Created -- ------ ---------- ----- ------ ------- geekBE R - 2.28G static 2013-11-19 10:19 solaris N / 37.0K static 2013-11-19 02:41
If you can see now, the size of geekBE is 2.28 GB, as its active BE now.
We can also mount a BE to see the contents of it.
# beadm mount geekBE /mnt
Similarly to umount it :
# beadm umount geekBE
To list a complete information about the new BE we created :
# beadm list -a geekBE BE/Dataset/Snapshot Active Mountpoint Space Policy Created ------------------- ------ ---------- ----- ------ ------- geekBE rpool/ROOT/geekBE R - 2.11G static 2013-11-19 10:19 rpool/ROOT/geekBE/var - - 129.20M static 2013-11-19 10:19 rpool/ROOT/geekBE/var@2013-11-19-04:49:13 - - 42.0K static 2013-11-19 10:19 rpool/ROOT/geekBE/var@install - - 38.56M static 2013-11-19 02:45 rpool/ROOT/geekBE@2013-11-19-04:49:13 - - 308.0K static 2013-11-19 10:19 rpool/ROOT/geekBE@install - - 6.46M static 2013-11-19 02:45
Installing packages in BE
You can install a package in a particular BE. If the BE is already active the you have to simply use the original pkg install command.
In case you want to add a package by creating a new BE :
# pkg install --be-name newBE vim
Packages to install: 1
Create boot environment: Yes
Create backup boot environment: No
DOWNLOAD PKGS FILES XFER (MB) SPEED
Completed 1/1 1528/1528 7.8/7.8 0B/s
PHASE ITEMS
Installing new actions 1673/1673
Updating package state database Done
Updating image state Done
Creating fast lookup database Done
A clone of solaris exists and has been updated and activated.
On the next boot the Boot Environment newBE will be
mounted on ‘/’. Reboot when ready to switch to this updated BE.
Snapshots of BE
We can also take snapshots of BEs similar to the ZFS file system snapshots.
# beadm create geekBE@monday
The -s option in beadm list would also display the snapshot we just created
# beadm list -s geekBE BE/Snapshot Space Policy Created ----------- ----- ------ ------- geekBE geekBE@2013-11-19-05:47:00 311.0K static 2013-11-19 11:17 geekBE@install 6.51M static 2013-11-19 02:45 geekBE@monday 0 static 2013-11-19 11:24
We can also create new BEs using the snapshots.
# beadm create -e geekBE@monday newBE
## beadm list BE Active Mountpoint Space Policy Created -- ------ ---------- ----- ------ ------- geekBE R - 2.31G static 2013-11-19 11:17 newBE - - 60.0K static 2013-11-19 11:27 solaris N / 90.0K static 2013-11-19 02:41
# beadm list BE Active Mountpoint Space Policy Created -- ------ ---------- ----- ------ ------- geekBE - - 150.0K static 2013-11-19 10:31 newBE R - 2.41G static 2013-11-19 10:36 solaris N / 2.78M static 2013-11-19 02:41
When you install the vim package by creating a new BE, it gets automatically created and activated as well on next reboot.
Destroying BE
In order to destroy a BE use :
# beadm destroy newBE Are you sure you want to destroy newBE? This action cannot be undone(y/[n]): y The BE that was just destroyed was the 'active on boot' BE. solaris is now the 'active on boot' BE. Use 'beadm activate' to change it.
I hope the post was informative. Stay tuned for more on Oracle Solaris 11.
Nice example for the power of boot environments
Tuesday, October 4. 2011
Assume you have a system, configured with all your application, everything is running fine. So you think it would be nice to have something like a freezed state of this situation. No problem. This command will do the trick.
# beadm create rescuenet # init 6
When you reboot your system you will see it as a new entry in the grub menu.
beadm activate already. Now i will drop the atomic bomb on your installation.
# rm --no-preserve-root -rf /
Essentially we’ve just nuked the installation. After a moment the system should just freeze. Reset the system and boot again via grub into the boot environment starting with «Oracle Solaris …»:
