How to resize the /boot partition?

Environment

• Red Hat Enterprise Linux (RHEL)

Issue

• Is it possible to increase/expand the size of /boot?
• How to extend /boot size?
• The filesystem /boot is out of space, how can it be resized?
• Boot partition out of room and we are unable to update the new kernel?
• Currently /boot shows:

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1        97M   89M  3.3M  97% /boot
/dev/sda2 ...

Resolution

• Uninstall older kernel versions and/or delete unwanted files. More details at: What is the proper method to remove old kernels from a Red Hat Enterprise Linux system?
• Re-install the system with a larger partition for /boot. The Red Hat Enterprise Linux's Installation Guide documentation provides the minimum recommended size for most users:

  • Red Hat Enterprise Linux 6 - Installation Guide - 9.15.5. Recommended Partitioning Scheme

  • Red Hat Enterprise Linux 7 - Installation Guide - 8.14.4.4. Recommended Partitioning Scheme

  • Red Hat Enterprise Linux 8:

    • Recommended partitioning scheme - Automatically installing RHEL
    • Recommended partitioning scheme - Interactively installing RHEL over the network
    • Recommended partitioning scheme - Interactively installing RHEL from installation media

  • Red Hat Enterprise Linux 9:

    • Recommended partitioning scheme - Automatically installing RHEL
    • Recommended partitioning scheme - Interactively installing RHEL over the network
    • Recommended partitioning scheme - Interactively installing RHEL from installation media

Root Cause

• Resizing the first partition on a disk is like adding acreage to a landlocked territory. It would be necessary to move back the other partitions on the disk and there is no supported process to accomplish this.
• Red Hat does not support resizing of the /boot partition. A re-install with a larger /boot partition is recommended.

Diagnostic Steps

Check size of /boot:

# df -h /boot

Check partition on boot device: (assuming /dev/sda):

# parted /dev/sda unit s print
Model: ATA HITACHI HTS72755 (scsi)
Disk /dev/sda: 976773168s
Sector size (logical/physical): 512B/4096B
Partition Table: msdos

Number  Start    End         Size        Type     File system  Flags
1      2048s    411647s     409600s     primary  ext4         boot
2      411648s  976773119s  976361472s  primary

In most cases, the following partition will start directly after the preceding one, so it would not be possible to extend /boot.

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