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sol14245: Overview of the recovery tasks performed from the MOS (11.x)
OverviewOverview

Original Publication Date: 03/04/2013
Updated Date: 08/05/2014

This article applies to BIG-IP 11.x. For information about other versions, refer to the following article:

Summary

The Maintenance Operating System (MOS) is an additional boot location that is automatically created when BIG-IP is installed.

Description

The BIG-IP system uses MOS for maintenance purposes. For example, the BIG-IP system automatically reboots into MOS to perform installations that require reformatting the drives. However, you can also manually boot the BIG-IP system into MOS at any time to perform certain recovery tasks. For example, if the BIG-IP system no longer boots from any of the normal boot locations, you can use MOS to retrieve important files before proceeding to reimage the system. For information, refer to the following procedures:

Booting the BIG-IP system into MOS
Using MOS to mount a volume and retrieve files

Configuring MOS for network access
Transferring files to/from the BIG-IP system while running MOS
Using MOS to perform an installation
 

Booting the BIG-IP system into MOS

To boot the BIG-IP system into MOS, perform the following procedure:

  1. Connect to the serial console of the BIG-IP system.
  2. Turn on or reset the BIG-IP system.
  3. When the GRUB menu is displayed, stop the boot process by pressing the down arrow key.
  4. Select TMOS maintenance from the menu.
  5. Press the Enter key.
  6. When prompted for the terminal type, press the Enter key to use vt100 emulation, or type the name of the terminal emulator that you are using.

Using MOS to mount a volume and retrieve files

To mount a volume and access its contents, perform the following procedure:

  1. Scan all disks for logical volumes by typing the lvscan command.

    The command output appears similar to the following example:

    ACTIVE '/dev/vg-db-sda/dat.share.1' [30.00 GB] normal
    ACTIVE '/dev/vg-db-sda/dat.log.1' [7.00 GB] normal
    ACTIVE '/dev/vg-db-sda/set.1.root' [256.00 MB] normal
    ACTIVE '/dev/vg-db-sda/set.1._usr' [1.34 GB] normal
    ACTIVE '/dev/vg-db-sda/set.1._config' [512.00 MB] normal
    ACTIVE '/dev/vg-db-sda/set.1._var' [3.00 GB] normal
    ACTIVE '/dev/vg-db-sda/set.2.root' [256.00 MB] normal
    ACTIVE '/dev/vg-db-sda/set.2._usr' [1.34 GB] normal
    ACTIVE '/dev/vg-db-sda/set.2._config' [512.00 MB] normal
    ACTIVE '/dev/vg-db-sda/set.2._var' [3.00 GB] normal
    ACTIVE '/dev/vg-db-sda/set.3.root' [256.00 MB] normal
    ACTIVE '/dev/vg-db-sda/set.3._usr' [1.25 GB] normal
    ACTIVE '/dev/vg-db-sda/set.3._config' [512.00 MB] normal
    ACTIVE '/dev/vg-db-sda/set.3._var' [3.00 GB] normal
    ACTIVE '/dev/vg-db-hda/dat.maint.1' [200.00 MB] normal
  2. Based on the output of the previous command, determine which logical volume contains the files that you want to retrieve. For example, if you want to retrieve the /config/bigip.conf file from the HD1.2 boot location, you must mount the /dev/vg-db-sda/set.2._config logical volume.

    Note: Some directories on the BIG-IP system are links to other directories. For example, the /var/tmp directory is a link to the /shared/tmp directory. Therefore, if you want to retrieve a file from the /var/tmp directory, you must mount the logical volume for the /shared directory.
  3. Create a temporary directory by typing the following command:

    mkdir /mnt/temp
  4. Mount the appropriate logical volume by using the following command syntax:

    mount <logical volume> /mnt/temp

    For example:

    mount /dev/vg-db-sda/set.2._config /mnt/temp
  5. Copy all required files from the mounted logical volume.

    For example:

    cp /mnt/temp/bigip.conf /
    cp /mnt/temp/bigip_base.conf /
  6. Unmount the logical volume by typing the following command:

    umount /mnt/temp
  7. Repeat this procedure until you have retrieved all necessary files.

Configuring MOS for network access

When the BIG-IP system is running MOS, the only configurable network interface is the management interface. Perform the following procedure to configure MOS for network access.

  1. To assign an IP address, netmask, and broadcast address to the management interface, use the following command syntax:

    ifconfig eth0 <ip> netmask <mask> broadcast <broadcast> up

    For example:

    ifconfig eth0 172.29.21.90 netmask 255.255.255.0 broadcast 172.29.21.255 up
  2. To configure a default gateway, use the following command syntax:

    route add default gw <ip>

    For example:

    route add default gw 172.29.21.1
  3. If you need DNS resolution, use the following command syntax to configure a nameserver:

    echo 'nameserver <ip>' > /etc/resolv.conf

    For example:

    echo 'nameserver 172.29.28.3' > /etc/resolv.conf
     

Transferring files to and from the BIG-IP system while running MOS

After you have configured MOS for network access, you can transfer files to and from the BIG-IP system using the scp utility.

  • Example of a file transfer from a remote host to the MOS environment:

    scp root@10.0.0.10:/root/BIGIP-10.2.0.1707.0.iso /
     
  • Example of a file transfer from the MOS environment to a remote host:

    scp /bigip.conf root@10.0.0.10:/root/

Note: MOS uses a temporary memory file system as its root file system; therefore, the available free space is approximately the same as the physical memory installed in the system. Therefore, on older platforms, you may not have enough free space to copy large files to the MOS environment. However, you do not need to copy an ISO image to the MOS environment to perform an installation. This process is covered in the next section.

Using MOS to perform an installation

You can use the image2disk utility to perform an installation while booted into MOS. For information about how to use the image2disk utility, type the image2disk --help command.

The image2disk utility accepts product repositories other than a local ISO image file. For example, it is possible to install BIG-IP using a remote HTTP server as the product repository. To do so, type a command similar to the following example:

image2disk --format=volumes --nosaveconfig http://10.0.0.10/10_2_0

Note: When the product repository is an HTTP URL, this must correspond to the root directory of a mounted CD/DVD or loopback-mounted ISO image file.

For information about using the image2disk utility with a local ISO image file, refer to SOL14558: Using the Maintenance Operation System to perform a local installation.

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