Changing and Resetting the Root Password
Changing and Resetting the Root Password RHEL 7 Setting up the root password is a mandatory part of the Red Hat Enterprise Linux 7 installation. If you forget or lose the root password it is possible to reset it, however users who are members of the wheel group can change the root password as follows: ~]$ sudo passwd root Note that in GRUB 2, resetting the password is no longer performed in single-user mode as it was in GRUB included in Red Hat Enterprise Linux 6. The root password is now ...
Creating Custom Unit Files
Creating Custom Unit Files Prepare the executable file with the custom service. This can be a custom-created script, or an executable delivered by a software provider. If required, prepare a PID file to hold a constant PID for the main process of the custom service. It is also possible to include environment files to store shell variables for the service. Make sure the source script is executable (by executing the chmod a+x) and is not interactive. Create a unit file in the /etc/systemd/...
Creating a second instance of the sshd service
Creating a second instance of the sshd service System Administrators often need to configure and run multiple instances of a service. This is done by creating copies of the original service configuration files and modifying certain parameters to avoid conflicts with the primary instance of the service. The following procedure shows how to create a second instance of the sshd service: Create a copy of the sshd_config file that will be used by the second daemon: ~]# cp /etc/ssh/sshd{,-second...
How to disable transparent hugepages (THP) on Red Hat Enterprise Linux 7, 8 and 9
How to disable transparent hugepages (THP) on Red Hat Enterprise Linux 7, 8 and 9 ・ How to disable transparent hugepages (THP) on Red Hat Enterprise Linux 7, 8 and 9.pdf | Environment Red Hat Enterprise Linux 7 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 transparent hugepages (THP) tuned Issue How to disable transparent hugepages (THP) on Red Hat Enterprise Linux 7, 8 and 9 Disabling transparent hugepages (THP) on Red Hat Enterprise Linux 7 is not taking effect. Resolution...
Introduction to grub 2
Introduction to grub 2 GRUB 2 Destination BIOS-based /boot/grub2/grub.cfg UEFI /boot/efi/EFI/redhat/grub.cfg Menu Entries in grub.cfg Examplemenuentry 'Red Hat Enterprise Linux Server' --class red --class gnu-linux --class gnu --class os$menuentry_id_option 'gnulinux-simple-c60731dc-9046-4000-9182-64bdcce08616' { load_video set gfxpayload=keep insmod gzio insmod part_msdos insmod xfs set root='hd0,msdos1' if [ x$feature_platform_search_hint = xy ]; th...
Relax-and-Recover (ReaR)
Relax-and-Recover (ReaR) RHEL 7.9 (Maipo) Setting up NFS server ・ Configuring NFS Server on Linux Installing ReaR ~]# yum install rear nfs-utils ・ Configuring Yum Repositories Configuring ReaR ReaR is configured in the /etc/rear/local.conf file. ~]# cat >> /etc/rear/local.conf << EOFOUTPUT=ISOOUTPUT_URL=nfs://192.168.3.112/nfsBACKUP=NETFSBACKUP_URL=nfs://192.168.3.112/nfsBACKUP_PROG_EXCLUDE=("${BACKUP_PROG_EXCLUDE[@]}" '/media' '/var/tmp' '/var/crash')NETFS_KEEP_OLD_BACKUP_C...
Duplicate PV Warnings for Multipathed Devices
Duplicate PV Warnings for Multipathed Devices SYMPTOMS 存储 LUN 做 LVM，执行 pvs 命令时，出现如下报错： ~]# pvsFound duplicate PV gdJ3qQtqoOjwZs2dtFw9vP0zIpz0HQhj: using /dev/sdba not /dev/emcpoweraiFound duplicate PV 8jLc3hNNwiSnGz4fEEasw8PQwthrGBpO: using /dev/sdbq not /dev/emcpowersFound duplicate PV BY29XsIxW1I4LUOcoqAepnG7eGUcPxZl: using /dev/emcpoweru not /dev/sdbo CAUSE 在默认配置下，LVM 对所有磁盘进行扫描，以确定哪一块上面包含 PV。如果使用了 device-mapper-multipath 或其他多路径软件如 EMC PowerPath 或 Hitachi Dynamic Link Manager (HDLM)，那么对于...
Oracle Exadata Virtual Machine 11.2.3.3.1
Oracle Exadata Virtual Machine 11.2.3.3.1 Cell Node 软件包下载 可到 Oracle Software Delivery Cloud 下载 V46145-01.zip，V27570-01.zip。 V46145-01.zip 为 Exadata Cell 11.2.3.2 介质。 V27570-01.zip 为 OracleLinux-R5-U7-Server-x86_64-dvd.iso。 Oracle 安装包：p10404530_112030_Linux-x86-64_1of7.zip; p10404530_112030_Linux-x86-64_2of7.zip。 Grid 安装包：p10404530_112030_Linux-x86-64_3of7.zip。 配置 hosts，修改启动内核 echo "192.168.184.160 oradb01" >>/etc/hostsecho "192.168.184.170 oracell01" >>/etc/hostssed -i 's/^d...
Resetting root password on VCSA
Resetting root password on VCSA Cause For passwords that have expired, the default vCenter Server Appliance password expires after 90 days. For more information, see Change the Password and Password Expiration Settings of the Root User Solution For 6.5 / 6.7 / 7.x ・ Resetting root password in vCenter Server Appliance 6.5 / 6.7 / 7.x (2147144) Take a snapshot or backup of the vCenter Server Appliance before proceeding. Caution: Do not skip this step Note: If the vCenter Appliance is on t...
Setting Shared Disks for Oracle RAC
Setting Shared Disks for Oracle RAC Create Disks. vmkfstools -c 1G -d eagerzeroedthick /vmfs/volumes/datastore01/Oracle-RAC/Oracle-RAC-OCR01-1GB.vmdkvmkfstools -c 1G -d eagerzeroedthick /vmfs/volumes/datastore01/Oracle-RAC/Oracle-RAC-OCR01-1GB.vmdkvmkfstools -c 1G -d eagerzeroedthick /vmfs/volumes/datastore01/Oracle-RAC/Oracle-RAC-OCR01-1GB.vmdkvmkfstools -c 30G -d eagerzeroedthick /vmfs/volumes/datastore01/Oracle-RAC/Oracle-RAC-MGMT01-30GB.vmdkvmkfstools -c 10G -d eagerzeroedthick /vmfs/v...
