Appendix A. Tools and tips for troubleshooting and bug reporting
The troubleshooting information in the following sections might be helpful when diagnosing issues at the start of the installation process. The following sections are for all supported architectures. However, if an issue is for a particular architecture, it is specified at the start of the section.
A.1. Dracut
Dracut
is a tool that manages the initramfs
image during the Linux operating system boot process. The dracut
emergency shell is an interactive mode that can be initiated while the initramfs
image is loaded. You can run basic troubleshooting commands from the dracut
emergency shell. For more information, see the Troubleshooting section of the dracut
man page on your system.
A.2. Using installation log files
For debugging purposes, the installation program logs installation actions in files that are located in the /tmp
directory. These log files are listed in the following table.
Log file | Contents |
---|---|
| General messages. |
| All external programs run during the installation. |
| Extensive storage module information. |
| dnf and rpm package installation messages. |
|
Information about the |
| Configuration information that is not part of other logs and not copied to the installed system. |
| Hardware-related system messages. This file contains messages from other Anaconda files. |
If the installation fails, the messages are consolidated into /tmp/anaconda-tb-identifier
, where identifier is a random string. After a successful installation, these files are copied to the installed system under the directory /var/log/anaconda/
. However, if the installation is unsuccessful, or if the inst.nosave=all
or inst.nosave=logs
options are used when booting the installation system, these logs only exist in the installation program’s RAM disk. This means that the logs are not saved permanently and are lost when the system is powered down. To store them permanently, copy the files to another system on the network or copy them to a mounted storage device such as a USB flash drive.
A.2.1. Creating pre-installation log files
You can set the inst.debug
option to create log files before the installation process starts. These log files contain, for example, the current storage configuration.
Prerequisites
- The Red Hat Enterprise Linux boot menu is open.
Procedure
- Select the Install Red Hat Enterprise Linux option from the boot menu.
- Press the Tab key on BIOS-based systems or the e key on UEFI-based systems to edit the selected boot options.
Append
inst.debug
to the options. For example:vmlinuz ... inst.debug
vmlinuz ... inst.debug
Copy to Clipboard Copied! -
Press the Enter key on your keyboard. The system stores the pre-installation log files in the
/tmp/pre-anaconda-logs/
directory before the installation program starts. - Press Ctrl + Alt + F2 to switch to the console and access the log files.
Change to the
/tmp/pre-anaconda-logs/
directory:cd /tmp/pre-anaconda-logs/
# cd /tmp/pre-anaconda-logs/
Copy to Clipboard Copied!
A.2.2. Transferring installation log files to a USB drive
Use this procedure to transfer installation log files to a USB drive.
Prerequisites
- You have backed up data from the USB drive.
- You are logged into a root account and you have access to the installation program’s temporary file system.
Procedure
- Press Ctrl + Alt + F2 to access a shell prompt on the system you are installing.
Connect a USB flash drive to the system and run the
dmesg
command:dmesg
# dmesg
Copy to Clipboard Copied! A log detailing all recent events is displayed. At the end of this log, a set of messages is displayed. For example:
[ 170.171135] sd 5:0:0:0: [sdb] Attached SCSI removable disk
[ 170.171135] sd 5:0:0:0: [sdb] Attached SCSI removable disk
Copy to Clipboard Copied! -
Note the name of the connected device. In the above example, it is
sdb
. Navigate to the
/mnt
directory and create a new directory that serves as the mount target for the USB drive. This example uses the nameusb
:mkdir usb
# mkdir usb
Copy to Clipboard Copied! Mount the USB flash drive onto the newly created directory. In most cases, you do not want to mount the whole drive, but a partition on it. Do not use the name
sdb
, use the name of the partition you want to write the log files to. In this example, the namesdb1
is used:mount /dev/sdb1 /mnt/usb
# mount /dev/sdb1 /mnt/usb
Copy to Clipboard Copied! Verify that you mounted the correct device and partition by accessing it and listing its contents:
cd /mnt/usb
# cd /mnt/usb
Copy to Clipboard Copied! ls
# ls
Copy to Clipboard Copied! Copy the log files to the mounted device.
cp /tmp/*log /mnt/usb
# cp /tmp/*log /mnt/usb
Copy to Clipboard Copied! Unmount the USB flash drive. If you receive an error message that the target is busy, change your working directory to outside the mount (for example, /).
umount /mnt/usb
# umount /mnt/usb
Copy to Clipboard Copied!
A.2.3. Transferring installation log files over the network
You can transfer installation log files over the network.
Prerequisites
- You are logged into a root account and you have access to the installation program’s temporary file system.
Procedure
- Press Ctrl + Alt + F2 to access a shell prompt on the system you are installing.
Switch to the
/tmp
directory where the log files are located:cd /tmp
# cd /tmp
Copy to Clipboard Copied! Copy the log files onto another system on the network using the
scp
command:scp *log user@address:path
# scp *log user@address:path
Copy to Clipboard Copied! Replace user with a valid user name on the target system, address with the target system’s address or host name, and path with the path to the directory where you want to save the log files. For example, if you want to log in as
john
on a system with an IP address of 192.168.0.122 and place the log files into the/home/john/logs/
directory on that system, the command is as follows:scp *log john@192.168.0.122:/home/john/logs/
# scp *log john@192.168.0.122:/home/john/logs/
Copy to Clipboard Copied! When connecting to the target system for the first time, the SSH client asks you to confirm that the fingerprint of the remote system is correct and that you want to continue:
The authenticity of host '192.168.0.122 (192.168.0.122)' can't be established. ECDSA key fingerprint is a4:60:76:eb:b2:d0:aa:23:af:3d:59:5c:de:bb:c4:42. Are you sure you want to continue connecting (yes/no)?
The authenticity of host '192.168.0.122 (192.168.0.122)' can't be established. ECDSA key fingerprint is a4:60:76:eb:b2:d0:aa:23:af:3d:59:5c:de:bb:c4:42. Are you sure you want to continue connecting (yes/no)?
Copy to Clipboard Copied! - Type yes and press Enter to continue. Provide a valid password when prompted. The files are transferred to the specified directory on the target system.
A.3. Verifying boot media
Verifying ISO images helps to avoid problems that are sometimes encountered during installation. These sources include DVD and ISO images stored on a disk or NFS server. You can test the integrity of an ISO-based installation source before using it to install Red Hat Enterprise Linux.
Prerequisites
- You have accessed the Red Hat Enterprise Linux boot menu.
Procedure
- From the boot menu, select Test this media & install Red Hat Enterprise Linux 10 to test the boot media.
- The boot process tests the media and highlights any issues.
-
Optional: You can start the verification process by appending
rd.live.check
to the boot command line. For more information, see Customizing boot options.
A.4. Display settings and device drivers
Some video cards have trouble booting into the Red Hat Enterprise Linux graphical installation program. If the installation program does not run using its default settings, it attempts to run in a lower resolution mode. If that fails, the installation program attempts to run in text mode.
There are several possible solutions to resolve display issues, most of which involve specifying custom boot options:
For more information, see Console boot options.
Solution | Description |
---|---|
Use the basic graphics mode | You can attempt to perform the installation using the basic graphics driver. To do this, either select Troubleshooting > Install Red Hat Enterprise Linux in basic graphics mode from the boot menu. |
Use the text mode | You can attempt to perform the installation using the text mode. For details, refer to Installing RHEL in text mode. |
Specify the display resolution manually | If the installation program fails to detect your screen resolution, you can override the automatic detection and specify it manually. To do this, append the inst.resolution=x option at the boot menu, where x is your display’s resolution, for example, 1024x768. For more information, see Customizing boot options. |
Use an alternate video driver | You can attempt to specify a custom video driver, overriding the installation program’s automatic detection. |
Perform the installation using RDP | If the above options fail, you can use a separate system to access the graphical installation over the network, using the Remote Desktop Protocol (RDP). |
- If specifying a custom video driver solves your problem, you should report it as a bug in Jira. The installation program should be able to detect your hardware automatically and use the appropriate driver without intervention.