Managing Interim Fixes on AIX

Technote (FAQ)


Question

What is an Interim Fix and how are they managed?

Answer

An interim fix, or ifix, for short, (previously called an emergency fix or efix) is a code update that is delivered by AIX technical support to resolve a specific known problem, or APAR, while an official PTF is undergoing the formal development process. Although ifixes are always tested before being made available, they are generally tested in very limited scope and within very limited configurations and have not been submitted to the same testing procedures as PTFs. Thus, you should only consider ifixes when the particular issue that you are encountering is causing an important negative impact to your business, where immediate relief is required and you cannot wait until the official PTF will become available. They are intended to be temporary and it is expected that the ifix will be removed from the system and replaced by the PTF at the earliest available service window.

Under the service strategy in effect for AIX at the time of this writing, ifixes may only be requested for systems running a version of AIX covered by the standard support agreement (usually the last two versions). Note that this excludes any AIX version that has reached the End of Support date, unless you have an Extended Support contract that includes ifix support. In addition, you will need to be running a Technology Level for which new fixes are being provided for your version of AIX. This currently includes any of the three most current Technology Levels for each supported version, or Technology Levels that are less than three years old. For versions of AIX that are under Extended Support, this will typically only include the last Technology Level released.

If a PTF for the APAR is available for the Technology Level that is installed on your system, support will recommend that you install the PTF. If your system is installed with a Technology Level for which new fixes are not being provided, you will be advised to update to a current Technology Level.

Every attempt will be made to provide an ifix, if one is requested, but an ifix may not be made available for complex problems. If you request a new ifix and already have an ifix installed, you may be required to install the PTF for the installed ifix before obtaining the new one.

When you request an ifix from AIX support, we may ask you to provide information about the target system, like a snap or the output of:

# emgr -lv3

The full AIX Service Strategy Details, including Technology Level Lifecycle and iFix Guidelines, can be found here: http://www14.software.ibm.com/webapp/set2/sas/f/best/home.html.


Using the emgr command to get information about an ifix package

To get information about an ifix package, use the command:

# emgr -d -e IZ12345.epkg.Z

You can also specify different levels of verbosity by using the -v flag. Level 1 is the default and level 3 is the maximum.


Using the emgr command to install an ifix

Ifixes are installed using the emgr command. The emgr command expects the ifix package to be in the compressed state, so don't try to uncompress the file that support provides you. The syntax is:

# emgr -e IZ12345.epkg.Z

You can also specify the -p flag to perform a preview of the installation operation.

When you install an ifix, the following occurs:

  • A check is made to ensure that the filesets that are affected by the ifix are not already locked by an ifix that's already installed.
  • A check is made to ensure that the appropriate fileset requisites are installed on the system.
  • A check is made to ensure that there is enough filesystem space on the system to install the ifix.
  • Any files that are to be replaced by the ifix are saved.
  • The files that the ifix delivers are copied into place on the system.
  • The filesets that are affected by the ifix are put into a LOCKED state to prevent further manipulation of the fileset. The fileset will be unlocked when the ifix is removed.
  • The system's boot image is rebuilt, if necessary, and a message is displayed indicating that the system should be rebooted. The system will not be rebooted automatically.

For full details on the ifix installation process see: http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=/com.ibm.aix.install/doc/insgdrf/emgr_installation_op.htm.


Using the emgr command to install concurrent ifixes

A concurrent ifix, a feature introduced in AIX 6.1, may be available for ifixes which fix a problem in the kernel, or certain kernel extensions. Traditionally, updates to these components require rebuilding the boot image and rebooting the system. A concurrent ifix can update the kernel or kernel extension in memory, without requiring a reboot. Only fixes that meet certain requirements are eligible to be built as concurrent ifixes and the final determination is made by IBM support on whether a concurrent ifix can be provided.

A concurrent ifix is initially installed to memory, then is optionally committed to disk, either at the time of installation, or at a later time. A concurrent ifix that is installed only in memory will not be loaded when the system reboots. Concurrent ifixes may also be installed in the traditional manner.

To install a concurrent ifix in the traditional manner:

# emgr -e IZ12345.epkg.Z

To install a concurrent ifix in memory only (the ifix will not be loaded when the system reboots):

# emgr -i IZ12345.epkg.Z

To commit a fix that is only installed in memory to disk, allowing it to be loaded when the system reboots:

# emgr -C -L IZ12345

To install an ifix in memory and commit it to disk in a single operation:

#emgr -Ci IZ12345.epkg.Z

Using the emgr command to list installed ifixes

You can list all of the ifixes installed on a system by running the command:

# emgr -l

You can list information about a specific installed ifix by running the command:

# emgr -l -L IZ12345

You can also specify different levels of verbosity by using the -v flag. Level 1 is the default and level 3 is the maximum.

The following lists some of the possible values for the state of ifixes:

S = Stable
The ifix was successfully installed in the traditional way (using the -e flag).
Q = Reboot Required
The ifix was installed successfully, but a reboot is required to fully integrate the fix into the system. After rebooting the ifix will be moved to the S, or Stable, state.
P = Patched
The concurrent ifix has been installed only to memory. System files have not been updated. A reboot will clear the ifix from memory.
N = Not Patched
The concurrent ifix is not loaded in memory. This can happen when a concurrent ifix is installed only in memory, then the system is rebooted.
SP = Stable + Patched
The concurrent ifix has been installed in memory and committed to disk.
QP = Reboot Required + Patched
The concurrent ifix was installed to memory and committed to disk, but the system has not been rebooted.
B = Broken
Something has gone wrong with the installation or removal of the ifix and should be corrected before relying on it working properly.

For a complete list of ifix states, please see http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=/com.ibm.aix.install/doc/insgdrf/emgr_efix_states.htm.


Checking that an ifix is installed properly

An ifix can be verified by running the command:

# emgr -c -L ifix_label

The -L flag and the ifix_label are optional. If a specific ifix is not specified, all installed ifixes will be verified. Also, various levels of checks can be made by using the -v flag. The default value is 1 and the maximum is 3.


Deinstalling or removing an ifix

You can deinstall an ifix by running the command:

# emgr -r -L IZ12345

You can also specify the -p flag to preview the deinstallation operation.

When an ifix is deinstalled, the following actions are taken:

  • A check is made to ensure that there is enough filesystem space to restore the original files that were saved during the ifix installation.
  • The affected filesets are unlocked.
  • The original files that were saved are replaced on the system.
  • The system's boot image is rebuilt, if necessary, and a message is displayed indicating that the system should be rebooted. The system will not be rebooted automatically.

Automatic removal of an ifix when installing the PTF

Starting in AIX 5.3 TL 10 and AIX 6.1 TL 3, the installp command will automatically remove an ifix from the system if you are installing the Technology Level, Service Pack, or PTF that provides the official fix for the problem. You will be notified which ifixes will be removed when performing a preview update operation and during the update operation itself. You may also have ifixes installed which cannot be mapped to a PTF. In this case, the update will fail because the fileset is locked by the ifix.

It is important to understand that if you perform an update operation and allow an ifix to be automatically removed, rejecting the update will not reinstall the ifix, even if you only installed the update in the Applied state. The Reject operation will, instead, replace the code that was delivered by the last Applied level of the fileset, not the code that was delivered by the ifix. Thus, if you wish to reject the update and go back to the ifix, you will need to reinstall the ifix once the update is rejected.

If you would like to take advantage of this functionality, but are not yet updated to AIX 5.3 TL 10 or AIX 6.1 TL 3, you may update the bos.rte.install fileset to either the 5.3.10.0 level or higher for AIX 5.3 systems, or 6.1.3.0 or higher for AIX 6.1 system. These filesets are available for download from the Fix Central web site and should be updated prior to installing the ifix. Also, only ifixes packaged after April 2009 will work with the automatic removal feature.

More details on automatic removal of ifixes is available in the IBM AIX Operating System Service Strategy Details and Best Practices paper, which can be found at: http://www14.software.ibm.com/webapp/set2/sas/f/best/home.html.

The Fix Central website can be accessed through: http://www-933.ibm.com/support/fixcentral/.


Managing ifixes in a NIM SPOT resource

To install an ifix into a NIM SPOT resource, place the ifix in an lpp_source in the emgr/ppc subdirectory. For example:

# lsnim -a location lpp1
lpp1:
   location = /export/lpp_source/lpp1
# ls -l /export/lpp_source/lpp1/emgr/ppc
-rw-r--r--   root   system  IZ12345.epkg.Z
Then, install the ifix using the cust operation:
# nim -o cust -a filesets=E:IZ12345.epkg.Z -a lpp_source=lpp1 spot1
or, using smitty:
# smitty nim_inst_latest
* Installation Target                                 spot1
* LPP_SOURCE                                          lpp1
* Software to Install                                [E:IZ12345.epkg.Z]      +

The E: tells the geninstall program that the software is packaged as an ifix and can be found in the emgr/ppc directory of the lpp_source. You may also create an installp_bundle resource, if you need to install multiple ifixes at once. Each ifix should be listed on a separate line of the bundle file.

To deinstall the ifix:

# nim -o maint -a filesets=E:IZ12345 -a installp_flags=u spot1

Managing ifixes in an altinst_rootvg

To create a copy of the rootvg and install an ifix to the altinst_rootvg:

# alt_disk_copy -d hdisk# -l /ifix_dir -w E:IZ12345.epkg.Z

To install an ifix into an altinst_rootvg that has already been created, you first perform a wake-up operation on the altinst_rootvg:

# alt_rootvg_op -Wd hdisk#
Then, you can install the ifix:
# alt_rootvg_op -Cw IZ12345.epkg.Z -l /ifix_dir

It is extremely important to put the altinst_rootvg back to sleep after the ifix has been installed:

# alt_rootvg_op -S

Managing ifixes in a multibos standby instance

The multibos command requires a bundle file that contains a list of the ifixes to be installed in geninstall bundle format. For example:

# cat ifixes.bnd
E:IZ12345.epkg.Z

To create a new multibos standby instance and install an ifix at the same time:

# multibos -Xsl /ifix_dir -b ifixes.bnd

To install an ifix into a multibos standby instance that has already been created:

# multibos -Xcl /ifix_dir -b ifixes.bnd

To deinstall the ifix, use the multibos shell function to open a shell in the standby instance of the OS:

# multibos -XS
Then, deinstall the ifix and exit the shell:
MULTIBOS> emgr -r -L IZ12345
MULTIBOS> exit
#

Special considerations for Trusted Execution environments

If you are using Trusted Execution on your system, the emgr command will verify the files that the ifix will replace. You will want to make sure that the following command does not return an error prior to installing the ifix:

# trustchk -q filename
for each file that the ifix delivers.

You can obtain a list of files delivered by an ifix by running:

# emgr -de IZ12345.epkg.Z

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