NAME | SYNOPSIS | DESCRIPTION | COMMANDS | OPTIONS | GLOBAL PARAMETERS | SCRIPT PARAMETERS | EXAMPLES | SEE ALSO | BUGS | COLOPHON

SYSTEMTAP(8)               System Manager's Manual              SYSTEMTAP(8)

NAME         top

       systemtap - SystemTap initscript service

SYNOPSIS         top

       service systemtap COMMAND [OPTIONS] [SCRIPT...]

DESCRIPTION         top

       The SystemTap initscript aims to provide a way to run scripts as a
       service and easily control them individually. Scripts can be
       configured to start upon manual request, or during system startup. On
       dracut-based systems, it is also possible to integrate scripts in the
       initramfs and have them start during early-boot.

       There are various parameters and options available to modify global
       behaviour, as well as script behaviour. Dependencies between scripts
       can be established so that starting one starts others.

       The configuration file of the initscript is located at
       ${prefix}/etc/systemtap/config. Acceptable parameters are detailed in
       the GLOBAL PARAMETERS section.

       Scripts must be placed in the ${prefix}/etc/systemtap/script.d
       directory and must have a .stp extension. When referring to them on
       the command-line however, there in no need to include the .stp
       extension.  Script names can only contain alphanumeric characters
       (and '_') and must not start with a number. The scripts directory may
       be changed by setting the SCRIPT_PATH parameter in the configuration
       file.

COMMANDS         top

       One of the commands below must be specified:

       start  Start SCRIPTs. If no scripts are specified, start the scripts
              specified by the DEFAULT_START configuration. If DEFAULT_START
              is not set, start all scripts in the script directory. For
              scripts already started, the command is ignored.  The command
              will fail if the scripts fail to start (see also the PASSALL
              configuration).

              If the AUTOCOMPILE configuration is on, the command will try
              to compile or update the specified scripts when one of the
              below conditions is true:

              - The compiled cache file does not exist.

              - The mtime (modified timestamp) of the original script file
                is newer than the time of the compiled script cache.

              - The specified stap options used to compile the script has
                been changed (see also the SCRIPT PARAMETERS section).

              - The result of `uname -a` has been changed.

       stop   Stop SCRIPTs. If no scripts are specified, stop all running
              scripts. For scripts already stopped, the command is ignored.
              The command will fail if the scripts fail to stop (see also
              the PASSALL configuration).

       restart
              Stop and start SCRIPTs.

       status Show the state of SCRIPTs and their dependencies.

       compile
              Compile SCRIPTs but do not start them. If the scripts have
              already been compiled, prompt for confirmation before
              overwriting cache. Compile for the current kernel, or the
              kernel release specified by the -r option.

       onboot Make SCRIPTs part of the initramfs so that they are started
              earlier during the boot process. This command is only
              available on dracut-based systems. If no scripts are
              specified, create a normal initramfs devoid of any SystemTap
              files.

              The initramfs is created for the current kernel, or the kernel
              release specified by the -r option. The path of the created
              initramfs defaults to /boot/initramfs-KVER.img, where KVER is
              the output of `uname -r`. The bootloader is also updated
              (using new-kernel-pkg(8)) to make the kernel entry use the new
              initramfs file. Use the -o option to specify a different path
              (the bootloader will not be updated).

              If the output file already exists, it is overwritten, unless
              the -b switch is given, in which case the file is appended
              .bak rather than overwritten.  However, if there is already a
              .bak version of the file, the backup will not be overwritten.

              WARNING: do not use the -o option of stap(1) with onboot
              scripts because the script is started before the root
              filesystem is even mounted.  Increase the buffer size if more
              space is needed.

       cleanup
              Delete the compiled SCRIPTs from cache. If no scripts are
              specified, then all compiled scripts are deleted. Only the
              cache for the current kernel is deleted, or the kernel release
              specified by the -r option. Prompt for confirmation before
              deleting.

OPTIONS         top

       Many of the commands can also take options. However, since users
       can't pass these options on boot, they are only meant for managing
       scripts after boot and for testing. Available options are:

       -c CONFIG_FILE
              Specify a different configuration file in place of the default
              one.

       -R     When using the start and stop commands, also include the
              scripts' dependencies (recursively).

       -r KERNEL_RELEASE
              When using the compile, onboot, and cleanup commands, specify
              the target kernel version rather than using the current one.
              Must be in the same format as `uname -r`.

       -y     Answer yes for all prompts.

       -o PATH.IMG
              When using the onboot command, specify the output path of the
              created initramfs. When specified, the bootloader
              configuration is not updated.

       -b     When using the onboot command, backup an existing initramfs
              image by adding a .bak extension rather than overwriting it.
              Without this option, the initramfs is overwritten.

GLOBAL PARAMETERS         top

       These parameters affect the general behaviour of the SystemTap
       initscript service. They can be specified in the configuration file.

       SCRIPT_PATH
              Specify the absolute path of the script directory. These are
              the scripts on which the initscript can operate. Scripts must
              have the .stp extension.  The default path is
              ${prefix}/etc/systemtap/script.d.

       CONFIG_PATH
              Specify the absolute path of the script configuration
              directory. These configuration files contain options for
              specific scripts. They must have the .conf extension. The
              default path is ${prefix}/etc/systemtap/conf.d.

       CACHE_PATH
              Specify the absolute path of the cache directory. The default
              path is ${prefix}/var/cache/systemtap.

       TEMP_PATH
              Specify the absolute path of the temporary directory in which
              SystemTap makes temporary directories to compile scripts. The
              default path is /tmp.

       STAT_PATH
              Specify the absolute path of the directory containing PID
              files used to track the status of SystemTap scripts. The
              default path is ${prefix}/var/run/systemtap.

       LOG_FILE
              Specify the absolute path of the log file. All messages are
              sent to this file, including compilation and runtime errors.
              The default path is ${prefix}/var/log/systemtap.log.

       PASSALL
              If this is set yes, initscript commands that operate on
              multiple scripts will report as failed when the action could
              not be performed on at least one script. If set to no, only a
              warning is emitted. The default is yes.

       RECURSIVE
              If this is set yes, the initscript will always follow script
              dependencies recursively. This means that there is no need to
              specify the -R option.  This flag is effective only if you
              specify script(s) from the command-line. The default is no.

       AUTOCOMPILE
              If this is set yes, the initscript automatically tries to
              compile specified scripts when needed if there is no valid
              cache. Otherwise, the related command simply fails. The
              default is yes.

       DEFAULT_START
              Specify scripts which will be started by default. If omitted
              (or empty), all scripts in the script directory will be
              started. The default is "".

       ALLOW_CACHEONLY
              If this is set yes, the initscript will also allow operating
              on scripts that are located in the cache directory, but not in
              the script directory. The default is no.

              WARNING: the initscript may load unexpected obsolete caches
              with this option.  The cache directory should be checked
              before enabling this option.

       LOG_BOOT_ERR
              Because boot-time scripts are run before the root filesystem
              is mounted, staprun's stderr cannot be logged to the LOG_FILE
              as usual. However, the log can instead be output to
              /var/run/systemtap/$script.log by setting LOG_BOOT_ERR to yes.
              If STAT_PATH is different from the default, the log files will
              be moved there upon executing any of the initscript commands.
              The default is no.

       Here is a global configuration file example:

              SCRIPT_PATH=/var/systemtap/script.d/
              PASSALL=yes
              RECURSIVE=no

SCRIPT PARAMETERS         top

       These parameters affect the compilation or runtime behaviour of
       specific SystemTap scripts. They must be placed in config files
       located in the CONFIG_PATH directory.

       <SCRIPT>_OPT
              Specify options passed to the stap(1) command for the SCRIPT.
              Here, SCRIPT is the name of the script file without the .stp
              extension. Note that the -F option is always added.

              The following options are ignored when compiling scripts: -p,
              -m, -r, -c, -x, -e, -s, -o, -h, -V, -k.

              The following options are ignored when running starting
              scripts: -h, -V, -v, -t, -p, -I, -e, -R, -r, -m, -k, -g, -P,
              -D, -b, -u, -q, -w, -l, -d, -L, -F, and all long options.

       <SCRIPT>_REQ
              Specify script dependencies (i.e. which script this script
              requires). For example, if foo.stp requires (or needs to run
              after) bar.stp, set

              foo_REQ="bar"

              Specify multiple scripts by separating their names by spaces.

       Here is a script configuration file example:

              script1_OPT="-o /var/log/script1.out"
              script2_OPT="-o /var/log/script2.out"
              script2_REQ="script1"

EXAMPLES         top

       INSTALLING SCRIPTS
              We first copy a SystemTap script (e.g. "script1.stp") into the
              script directory:

              # cp script1.stp /etc/systemtap/script.d/

              We can then set any script options, for example:

              # vi /etc/systemtap/conf.d/group1
              script1_OPT="-o /var/log/group1.out"

              We then install a script (e.g. "script2.stp") which needs to
              run after script1. In this case, we can do the following:

              # cp script2.stp /etc/systemtap/script.d/
              # vi /etc/systemtap/conf.d/group1
              script2_OPT="-o /var/log/group2.out"
              script2_REQ="script1"

              This way, if stap(1) fails to run script1, the initscript will
              not even try to run script2.

       TESTING
              After installing scripts, we can test that they work by simply
              doing:

              # service systemtap start
              # service systemtap stop

              We could be more specific as well, for example:

              # service systemtap start script1
              # service systemtap stop script1

              If there were no errors, we are ready to use it.

       ENABLING SERVICE
              After we're satisfied with the scripts and their tests, we can
              enable the SystemTap initscript service:

              # chkconfig systemtap on

       DELETING SCRIPTS
              Scripts are deleted by simply removing them from the script
              directory and removing any configuration lines specific to
              them:

              # rm /etc/systemtap/script.d/script2.stp
              # vi /etc/systemtap/conf.d/group1

              If the script is still running, we also need to stop it:

              # service systemtap stop script2

              We can then also remove the cache associated with the script:

              # service systemtap cleanup script2

       PREPARING FOR KERNEL UPDATES
              Usually, there is nothing to do when booting into a new ker‐
              nel. The initscript will see that the kernel version is dif‐
              ferent and will compile the scripts. The compilation can be
              done beforehand as well to avoid having to compile during boot
              by using the -r option:

              # service systemtap compile myscript -r <NEW_KERNEL_VERSION>

       IMPORTING COMPILED SCRIPTS
              For environments which lack compilation infrastructure (e.g.
              no compilers or debuginfo), such as a production system, the
              scripts can be compiled on another (development) machine and
              then transferred over to the production system:

              # service systemtap compile myscript -r \
              >   <KERNEL_VERSION_OF_TARGET_MACHINE>
              # tar czf stap-scripts-<kernel-version>.tar.gz \
              >   /var/cache/systemtap/<kernel-version> \
              >   /etc/systemtap/conf.d/<configfile>

              And then copy this package to the target machine and extract
              it.

       STARTING SCRIPTS DURING EARLY-BOOT
              The initscript also allows us to start scripts earlier during
              the boot process by creating an initramfs containing the
              script's module. The system must be dracut-based for this to
              work. Starting a script at this stage gives access to informa‐
              tion otherwise very hard to obtain.

              We first install the script by copying it into the script di‐
              rectory as usual and setting whatever options we'd like:

              # cp myscript.stp /etc/systemtap/script.d
              # vi /etc/systemtap/conf.d/myscript.conf

              To add the script to the initramfs, we use the onboot command:

              # service systemtap onboot myscript

              If the script is not already compiled and cached, it will be
              done at this point.  A new initramfs will then be created at
              the default location. We can use the -b option to ensure that
              the existing initramfs is backed up. We can then restart the
              system.

       USING A DIFFERENT INITRAMFS
              If we would prefer to only start the script for one boot and
              not others, it might be easier to instead use the -o option to
              specify a different initramfs output file:

              # service systemtap onboot myscript \
              >   -o /boot/special_initramfs.img

              Once the initramfs is created, it's simply a matter of chang‐
              ing the command-line options at boot-time so that the new im‐
              age is used rather than the usual one.

       CREATING AN INITRAMFS FOR A DIFFERENT KERNEL
              Just like the compile command, we can use the -r option to
              specify the kernel for which we want to create the initramfs.
              This is useful when we are about to upgrade and would like to
              prepare in advance. For example:

              # service systemtap onboot myscript \
              >   -r 3.12.6-200.fc19.x86_64

       REMOVING SCRIPTS FROM THE INITRAMFS
              Finally, to remove all script from the initramfs, we simple
              run the onboot command without specifying any scripts:

              # service systemtap onboot

              This will simply create a standard initramfs without any Sys‐
              temTap modules inserted.

       TROUBLESHOOTING EARLY-BOOT ISSUES
              There can be many reasons for which the module didn't insert
              or did not work as expected. It may be useful to turn on dra‐
              cut debugging by adding 'rdinitdebug' to the kernel command-
              line and checking dmesg/journalctl -ae. Also, the stderr out‐
              put of staprun can be captured by setting the LOG_BOOT_ERR op‐
              tion to yes.

SEE ALSO         top

       stap(1) dracut(8) new-kernel-pkg(8)

BUGS         top

       Use the Bugzilla link of the project web page or our mailing list.
       http://sourceware.org/systemtap/ , <systemtap@sourceware.org>.

COLOPHON         top

       This page is part of the systemtap (a tracing and live-system
       analysis tool) project.  Information about the project can be found
       at ⟨https://sourceware.org/systemtap/⟩.  If you have a bug report for
       this manual page, send it to systemtap@sourceware.org.  This page was
       obtained from the project's upstream Git repository 
       ⟨git://sourceware.org/git/systemtap.git⟩ on 2017-04-25.  If you dis‐
       cover any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

                                                                SYSTEMTAP(8)

Pages that refer to this page: stap(1)