OS - FAQ
- The disk has been changed to Read Only on Red Hat Enterprise Linux (or CentOS / Ubuntu). How should I take actions?ECL2.0, OS
If a problem (such as an "I/O" error) occurs during a disk access to a device, the file system of a device mounted in a specific directory might be forced tot be remounted with Read Only because it is determined that a problem has occurred with the file system of the device.In this case, you can remount the file system of the device mounted in a specific directory with Read Write according to below steps.
1.Check the file system of the device mounted with Read Only (in the example below, you can confirm that "/dev/vdb" is mounted with Read Only)
# mount -l /dev/mapper/rhel-root on / type xfs (rw,relatime,attr2,inode64,noquota) /dev/mapper/rhel-var on /var type xfs (rw,relatime,attr2,inode64,noquota) /dev/vda1 on /boot types xfs (rw,relatime,attr2,inode64,noquota) /dev/vdb on /mnt types xfs (ro,relatime,attr2,inode64,noquota) ※ ro = read only
2.Remount the file system of the device with Read Write (In the example below, "/dev/vdb" has been remounted with Read Write)
# mount -o remount,rw /dev/vdb # mount -l /dev/mapper/rhel-root on / type xfs (rw,relatime,attr2,inode64,noquota) /dev/mapper/rhel-var on /var type xfs (rw,relatime,attr2,inode64,noquota) /dev/vda1 on /boot types xfs (rw,relatime,attr2,inode64,noquota) /dev/vdb on /mnt types xfs (rw,relatime,attr2,inode64,noquota) ※ rw = read write
- Red Hat Enterprise Linux (or CentOS) does not boot.ECL2.0, OS
Follow the steps below to acquire boot logs to investigate why Red Hat Enterprise Linux (or CentOS) does not boot.
1. Boot Red Hat Enterprise Linux (or CentOS) in rescue mode.
2. Execute the following command to acquire the boot logs.
# journalctl -xb | less
If the following logs exist in Red Hat Enterprise Linux (or CentOS) boot logs, the description of "/etc/ fstab" is not appropriate.
By commenting out or deleting the line where the description of "/etc / fstab" is not appropriate, you could normally boot Red Hat Enterprise Linux (or CentOS).
(e.g.) The mount option is not specified properly in "/etc/fstab".
Jan 01 00:00:00 localhost systemd: Mounting /mnt... Jan 01 00:00:00 localhost mount: mount: wrong fs type, bad option, bad superblock on /mnt, Jan 01 00:00:00 localhost mount: missing codepage or helper program, or other error Jan 01 00:00:00 localhost mount: In some cases useful info is found in syslog - try Jan 01 00:00:00 localhost mount: dmesg | tail or so. Jan 01 00:00:00 localhost kernel: XFS (vdb): unknown mount option [default]. ※ There is a description of non-existent mount option "default" in "/etc/fstab". Jan 01 00:00:00 localhost systemd: mnt.mount mount process exited, code=exited status=32 Jan 01 00:00:00 localhost systemd: Failed to mount /mnt.
(e.g.) The device is not specified properly in "/etc/fstab".
Jan 01 00:00:00 localhost systemd: Job dev-vdc.device/start timed out. ※ There is a description of non-existent device "/dev/vdc" in "/etc/fstab".
- What is the procedure for booting in rescue mode on RHEL (or CentOS)?ECL2.0, OS
The procedure for booting RHEL (or CentOS) currently in use on a virtual server in rescue mode is as follows.
1. Log in to the cloud computing control panel.
2. Go ahead [Server]-[Virtual Server]-[Instance]-[Console] and open the console screen of the virtual server instance.
3. Press [Send CtrlAltDelete] button on the console screen.
4. Press [e] key on the GRUB Boot screen (OS selection screen for booting) immediately after starting the virtual server instance.
5. Delete "console = ttyS0 console = ttyS1,115200n8 quiet" at the end of the line starting with "linux16" on the edit screen, enter "systemd.unit = rescue.target" and enter "Ctrl" "x" at the same time.
# When using the Japanese keyboard, it may be difficult to enter "=". In this case, please leave "=" when deleting "console = ttyS0 console = ttyS1,115200n8 quiet".
6. Log in using the root user password on the Red Hat Enterprise Linux or CentOS login screen.
Red Hat - Product Documentation
URL : https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/sec-terminal_menu_editing_during_boot
- Is the SID (Security Identifier) of Windows Server changed by snapshot duplication or system restore of the backup menu?Backup, ECL2.0, OS, Virtual Server
- Is it possible to use Windows Server from private ISO on Virtual Server?ECL2.0, OS, Virtual Server
- Is Internet connection required for Windows Update on barematal server or virtual server?ECL2.0, OS
Yes. Please apply for Internet connectivity if you want to execute Windows Update on barematal server or virtual server.
- How do I set the language setting to Japanese on Windows OS?ECL2.0, OS
If you want to set the OS Language setting to Japanese, you can set it from the OS control panel yourself.
From the OS control panel, you can change the OS Language setting to Japanese in Add Language.
Reference: Service Descriptions - Windows Server
Although it becomes the specification of Microsoft Corporation, after the installation of the OS image, the process of automatically and periodically deleting unused Language Packs in the Windows OS is running, and this process might have deleted the Japanese package.
When deletion is executed, you can find the following log; "Package language pack was successfully changed to Absent state."
At first, please check whether Japanese pack exists or not in the Language Pack. If Japanese pack does not exist in the Language Pack, please download it after setting your server connected to the Internet.
- How can I perform yum update on a server created from RHEL official image template?ECL2.0, OS
Please confirm the following 3 points.
Please confirm that the connectivity from the virtual server to "169.254.127.18" and "169.254.127.19". These are RHUI provided in the common function pool.(Download destination of yum update in RedhatOS, official template provided by NTT Com)
Please check "/etc /hosts".
If there is no setting required for name resolution of the target repository server, it is necessary to add the setting. The following settings are required in "/ etc / hosts" of the target VM.
169.254.127.18 rhcds0001-jp1 rhcds0001-jp1.ecl.ntt.com.local 169.254.127.19 rhcds0001-jp1 rhcds0002-jp1.ecl.ntt.com.local
Since April 2018, the repository server of yum has become new, and customers need to change the setting on the server's guest OS.
Please refer to the following for details.
- The Windows Server created from the official template is in operation. Can I still use it after Microsoft's support?ECL2.0, OS
Even after the end of support, you can use the corresponding server.
However, we will not support OS whose Microsoft's support expired. We will not extend the support period.
- License activation fails on the virtual server created from Windows Server Official Image Template.ECL2.0, OS, Virtual Server
There is a possibility that connectivity to the license server provided by NTT Com may not be established.
Follow the steps below to ensure connectivity to the license server.
In order to implement OS license authentication, a common function gateway is required.When using Windows Server, please make sure to apply common function gateway.
Also, if the common function gateway is removed, OS license authentication will be lost. Therefore, please be careful not to remove the common function gateway from the Windows Server that you are using.