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sol12509: Overview of the recovery tasks performed from the Maintenance Operating System (MOS) (10.x)
OverviewOverview

Original Publication Date: 01/14/2011
Updated Date: 03/04/2013

This article applies to BIG-IP 10.x. For information about other versions, refer to the following article:

The Maintenance Operating System (MOS) is an additional boot location that is automatically created when BIG-IP version 10.x is installed. The BIG-IP system uses MOS for maintenance purposes. For example, the BIG-IP system automatically reboots into MOS to perform version 10.x 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.

This Solution covers the following topics:

Booting the BIG-IP system into MOS
Using MOS to mount a volume and retrieve files
Using MOS to mount a partition and retrieve files
Configuring MOS for network access
Transferring files to/from the BIG-IP system while running MOS
Using MOS to perform a version 10.x 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.

    Note: For more information, refer to SOL7683: Connecting a serial terminal to a BIG-IP system.
  2. Power 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 and press Enter.
  5. When prompted for the terminal type, press Enter to use vt100 emulation, or type the name of the terminal emulator you are using.
     

Using MOS to mount a volume and retrieve files

If the BIG-IP system is formatted with the volumes disk-formatting scheme, perform the following procedure to mount a volume and access its contents:

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

    The command output will appear 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 typing the following command:

    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 all necessary files have been retrieved.
     

Using MOS to mount a partition and retrieve files

If the BIG-IP system is formatted with the partitions disk-formatting scheme, perform the following procedure to mount a partition and access its contents:

  1. Based on the information provided by the following tables, determine which partition contains the files that you want to retrieve.

    Mount Point Partition for boot location HD1.1 Partition for boot location HD1.2
    / /dev/<hard disk>5 /dev/<hard disk>10
    /config /dev/<hard disk>7 /dev/<hard disk>12
    /usr /dev/<hard disk>8 /dev/<hard disk>14
    /var /dev/<hard disk>9 /dev/<hard disk>13
    /shared /dev/<hard disk>1 /dev/<hard disk>1

    Platform Hard Disk
    1500 and 4100 hda
    3400, 6400 and 6800 hdc
    4500, 8400, 8800, 1600, 3600, 3900, 6900 and 8900 sda

    For example, if you want to retrieve the /config/bigip.conf file from the HD1.2 boot location of a BIG-IP 1600 system, you must mount the /dev/sda12 partition.

    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 partition for the /shared directory.
  2. Create a temporary directory by typing the following command:

    mkdir /mnt/temp
  3. Mount the appropriate partition by typing the following command:

    mount <partition> /mnt/temp

    For example:

    mount /dev/sda12 /mnt/temp
  4. Copy all required files from the mounted partition.

    For example:

    cp /mnt/temp/bigip.conf /
    cp /mnt/temp/bigip_base.conf /
  5. Unmount the partition by typing the following command:

    umount /mnt/temp
  6. Repeat this procedure until all necessary files have been retrieved.
     

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. Type the following command to assign an IP address, netmask, and broadcast address to the management interface:

    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. Type the following command to configure a default gateway:

    route add default gw <ip>

    For example:

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

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

    For example:

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

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

Once you have configured MOS for network access, you can transfer files to and from the BIG-IP system using the scp utility. Two example commands are provided below:

  • 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 filesystem as its root filesystem; therefore, the free space available to you will be approximately the same as the physical memory installed in the system. This means that on older platforms, you may not have enough free space to copy large files to the MOS environment. However, you should note that you do not need to copy an ISO image to the MOS environment to perform a version 10.x installation. This process is covered in the next section.
 

Using MOS to perform a version 10.x installation

You can use the image2disk utility to perform a version 10.x 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 version 10.x using a remote HTTP server as the product repository. To do so, you would type a command similar to the following example:

image2disk --instslot=HD1.1 --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.

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