Developer FAQ
How to run a job that automatically fails?
I want to run a job that automatically fails to simulate failing jobs.
To do so, you can use the directive Client Run Before Job (Dir->Job).
This directive launches a script on the client-side (file daemon) by default before running the job.
set the script to be “/bin/false”
or, if you want a job to work properly but fail at the end (e.g: simulate a full backup that did not go well), you can do the following
I have changes that affect tapes and autochangers, how can I test them?
In order to test tapes, we use mhvtl to simulate the presence of tape and autochanger devices.
Documentation is available at https://www.mhvtl.com/
Some distributions, like openSUSE, offer mhvtl packages that you can download and install using your package manager. Otherwise you need to clone the mhvtl repository from https://github.com/markh794/mhvtl.git. Then you should compile and install the mhvtl kernel module
$ git clone https://github.com/markh794/mhvtl.git
$ cd mhvtl/kernel
$ make
$ sudo make install
After that you have to install the mhvtl user tools
$ cd mhvtl
$ make
$ sudo make install
Now that mhvtl is installed, you can enable and start the mhvtl services
$ sudo systemctl enable --now mhvtl-load-modules.service
$ sudo systemctl enable --now mhvtl.target
In order to check if your installation was done correctly, you can run lsscsi (install it if you don’t have it) or ls /dev/tape/by-id which should give you something similar to the following output
$ lsscsi
[1:0:0:0] disk ATA SAMSUNG MZ7TY256 3L6Q /dev/sda
[2:0:0:0] mediumx STK L700 0107 /dev/sch1
[2:0:1:0] tape IBM ULT3580-TD8 0107 /dev/st1
[2:0:2:0] tape IBM ULT3580-TD8 0107 /dev/st2
[2:0:3:0] tape IBM ULT3580-TD8 0107 /dev/st0
[2:0:4:0] tape IBM ULT3580-TD8 0107 /dev/st6
[2:0:8:0] mediumx STK L80 0107 /dev/sch0
[2:0:9:0] tape STK T10000B 0107 /dev/st7
[2:0:10:0] tape STK T10000B 0107 /dev/st4
[2:0:11:0] tape STK T10000B 0107 /dev/st3
[2:0:12:0] tape STK T10000B 0107 /dev/st5
$ ls /dev/tape/by-id/
scsi-350223344ab000100 scsi-350223344ab001000 scsi-XYZZY_A3
scsi-350223344ab000100-nst scsi-350223344ab001000-nst scsi-XYZZY_A3-nst
scsi-350223344ab000200 scsi-350223344ab001100 scsi-XYZZY_A4
scsi-350223344ab000200-nst scsi-350223344ab001100-nst scsi-XYZZY_A4-nst
scsi-350223344ab000300 scsi-SSTK_L700_XYZZY_A scsi-XYZZY_B1
scsi-350223344ab000300-nst scsi-SSTK_L80_XYZZY_B scsi-XYZZY_B1-nst
scsi-350223344ab000400 scsi-XYZZY_A1 scsi-XYZZY_B2
scsi-350223344ab000400-nst scsi-XYZZY_A1-nst scsi-XYZZY_B2-nst
scsi-350223344ab000900 scsi-XYZZY_A2 scsi-XYZZY_B3
scsi-350223344ab000900-nst scsi-XYZZY_A2-nst scsi-XYZZY_B3-nst
Now that the installation is done, you will have to let bareos know that you are building tape and autochanger tests by adding the needed devices as cmake parameters to your exisiting cmake configuration:
-Dchanger-device=/dev/tape/by-id/scsi-SSTK_L700_XYZZY_A
-Dtape-devices=/dev/tape/by-id/scsi-350223344ab000100-nst;/dev/tape/by-id/scsi-350223344ab000200-nst;/dev/tape/by-id/scsi-350223344ab000300-nst;/dev/tape/by-id/scsi-350223344ab000400-nst
The selected devices are the ones used in our tests.
A machine reboot can solve most of issues like missing devices or other incoherences.
For any update of kernel and kernel headers, you will have to rebuild and reinstall mhvtl, otherwise mhvtl kernel module loading will fail, mhvtl will not work properly and bareos will not build.
mhvtl updates in certain rare cases can change tape names causing tests to fail. In that case, check /etc/mhvtl/device.conf and modify the device names accordingly.