The Problem Oracle Real Application Clusters (RAC) servers run on CentOS/RHEL 7 and utilizing ASMLib-managed iSCSI multipathed disks. Upon server reboot, Oracle ASMLib disks are not automatically discovered at boot time causing Oracle Cluster Ready Services (CRS) to fail to start. ASM disks are, however, correctly discovered when manually running the oracleasm scandisks command soon after the server reboot. Following is the oracleasm configuration # cat … [Read more...] about ASMLib-Managed Disks on Multipathed iSCSI Targets are not Discovered after Server Reboot in CentOS/RHEL 7
How to load SELinux Module For Oracleasm
Question: How to load the SELinux module for oracleasm? When searching for the selinux oracleasm module with the locate command it may return as if the file exists: # locate /oracleasm.pp /etc/selinux/targeted/modules/active/modules/oracleasm.pp However, when running the command semodule to load the oracleasm.pp module it fails: # semodule --verbose -i /etc/selinux/targeted/modules/active/modules/oracleasm.pp Attempting to install module … [Read more...] about How to load SELinux Module For Oracleasm
“Metadata File Does Not Match Checksum” Issue When Yum Installs or Updates Package
The Problem Scenario 1: The user is unable to perform "yum install oracle-rdbms-server-11gR2-preinstall". The yum tries to download the latest metadata ("http://public-yum.oracle.com/repo/OracleLinux/OL6/latest/x86_64/repodata/primary.xml.gz" ) and rejects it with the error message "[Errno -1] Metadata file does not match checksum". Upon this, yum tries the next mirror where it encounters the same error and goes to the next mirror and so on until it have tried all mirrors and ends with … [Read more...] about “Metadata File Does Not Match Checksum” Issue When Yum Installs or Updates Package
How to install/get packages from Oracle EPEL Repository on OEL 7
Question: How to install/get packages from Oracle EPEL Repository on OL7? 1. Create a repo file like /etc/yum/repos.d/epel-yum-ol7.repo. For example: # cat /etc/yum.repos.d/epel-yum-ol7.repo [ol7_epel] name=Oracle Linux $releasever EPEL ($basearch) baseurl=http://yum.oracle.com/repo/OracleLinux/OL7/developer_EPEL/$basearch/ gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-oracle gpgcheck=1 enabled=1 2. And then run "yum repolist" command to see if repository is in there. # yum … [Read more...] about How to install/get packages from Oracle EPEL Repository on OEL 7
“yum clean all” not clearing yum repository cache in CentOS/RHEL/OEL
The Problem "Yum clean all" not clearing the yum cache information under /var/cache/yum for orcle Linux server which use Oracle public yum repository or local yum repository. # yum repolist Loaded plugins: refresh-packagekit, security, ulninfo public_ol6_UEK_latest | 1.2 kB 00:00 public_ol6_UEK_latest/primary | 26 MB 00:04 public_ol6_UEK_latest 554/554 public_ol6_latest | 1.4 kB 00:00 public_ol6_latest/primary | 58 MB 00:04 public_ol6_latest 36051/36051 repo id repo name … [Read more...] about “yum clean all” not clearing yum repository cache in CentOS/RHEL/OEL
How To Enable PHP 7.0 And httpd24 On Oracle Linux 7
PHP7 is available and supported on OL7. The YUM distribution channel must be manually enabled for the RPM packages to be available: 1. Edit /etc/yum.repos.d/public-yum-ol7.repo file and make sure you enable "ol7_software_collections" repo. [ol7_software_collections] name=Software Collection Library release 3.0 packages for Oracle Linux 7 … [Read more...] about How To Enable PHP 7.0 And httpd24 On Oracle Linux 7
CentOS/RHEL: How to find the package with a missing file using YUM
Question: How to find the package with a missing file in the system using YUM? This how-to is also applicable when the file is not missing and is already installed, but for some reason, it is required to know the package that provides it. The YUM package manager tool uses repositories to retrieve information and download packages. The repositories configurations are at /etc/yum.repos.d/*.repo files and in these files it can be multiple repositories enabled and others disabled. 1. The sub … [Read more...] about CentOS/RHEL: How to find the package with a missing file using YUM
How to Access Docker Container’s Network Namespace from Host
This post is to illustrate how to access the docker container's network namespace. 1. Identify the docker container id you want to access and run below command as root on host. # docker ps 2. Get docker container's PID: # pid=$(docker inspect -f '{{.State.Pid}}' ${container_id}) 3. Create netns directory: # mkdir -p /var/run/netns/ 4. Create the name space softlink: # ln -sfT /proc/$pid/ns/net /var/run/netns/[container_id] 5. Run ip netns command to access this name … [Read more...] about How to Access Docker Container’s Network Namespace from Host
How To Change The Time Zone For A Docker Container
The goal of this post is to set up the timezone on the container to match the same timezone on the Docker server, this will allow users to see the same time in both instances (Docker Server and Container). Most of the time Containers do not use the same time as the Docker server, this post will show how to configure this. This is how this looks like before making the changes. Container Time: # docker exec 15c0c99b5c65 date Wed Aug 23 15:40:24 UTC 2019 Docker Server Time: # date Wed … [Read more...] about How To Change The Time Zone For A Docker Container
Understanding Ksplice Effective Kernel Version
This post will explain the meaning behind the output of the "ksplice kernel uname" (Ksplice Enhanced client) or "uptrack-uname" (Ksplice Uptrack client) command and how to interpret Ksplice's effective kernel version string. The effective kernel version that is reported by Ksplice when running the command "ksplice kernel uname -r" reflects the security position of the kernel that is running based on the patches that have been applied by Ksplice. This effective kernel version usually differs … [Read more...] about Understanding Ksplice Effective Kernel Version