OS Patch Management
We need to ensure that Virtual Machines within the HMCTS subscription are kept up to date in terms of OS patching. The patching approach will be on a quarterly basis unless a critical patch(es) have been identified. This document covers the patching process, patching instructions for each OS type and troubleshooting sections.
Patching Process
PlatOps resources confirmed to participate in patching, including out of hours.
A quarterly patching schedule needs to be created, reviewed, and approved (by PlatOps and the customer). The non-live environments for a service needs to be scheduled and successfully patched first prior to production.
Production services will require a change request and scheduled out of hours, for the agreed change window. Changes should be raised in advance to allow changes to be approved and resources/teams scheduled (i.e. applications and DBs to be shut down prior to patching and started after and tested.)
Patching Calendar consists of rota, server lists and services scheduled for patching per month.
High-level patching process: A lower environment will be patched prior to Production (example: Non-Live Environment (NLE) → Production). Ensure production changes are approved and at the implement status and window and resources have been approved and provided. Prior to patching (i.e. the day before) log into each server and do health checks to make sure no space issues and repos are setup correctly to pull down patches and scheduled backups are successful, etc. Ensure a valid backup is available prior to each environment/virtual machine being patched. For NLE check backups were successful from the last scheduled daily backup. For Production run a backup and proceed when completed. Check Patching Calendar Server Lists tab to verify the services to be patched and their servers and the patching notes tab to confirm if version upgrade is required as well as patching. Prior to any patching, Platform Operations will contact the Development team; they will be required to stop relevant services/shutdown databases etc. This initial process should be documented if not already. To include a restart schedule (example: restart app01 → db01 → app02 → db02 ) - this is to be provided by the Application team. Once restarts have been completed, development team to start & test applications. Once the above is successful, the next environment will be patched with similar steps.
Azure Update Manager
Azure Update Manager is a SaaS solution, to manage and govern software updates for Windows and Linux machines. As part of its deep integration with the Azure Portal, all Azure infrastructure in place and any VM’s created using Azure marketplace images, already include the necessary software. Removing all barriers to implementation.
The native software update feature within the operating system is utilised by Azure Update Manager (AUM), to first audit the patching requirements and then apply any updates. With scheduling and scope, controlled by AUM, with results reported back, via a single console.
Manual OS Patching Instructions
See instructions below on how to generate list and apply patching for each OS – RHEL, Ubuntu and Windows:
RHEL
1. Based on a standard RHEL 7.7 VM, yum-plugin-security is installed by default
[root@tamops-rhel ~]# yum install yum-plugin-security
Loaded plugins: langpacks, product-id, search-disabled-repos
Package yum-3.4.3-163.el7.noarch already installed and latest version
Nothing to do
2. Check for Security Critical Updates (Check for Critical Updates only)
[root@tamops-rhel ~]# yum --security --sec-severity=Critical check-update
--> maven30-maven-profile-2.2.1-47.7.el7.noarch from rhui-rhel-server-rhui-rhscl-7-rpms excluded (updateinfo)
--> python27-python-jinja2-2.6-15.el7.noarch from rhui-rhel-server-rhui-rhscl-7-rpms excluded (updateinfo)
--> maven30-maven-model-2.2.1-47.7.el7.noarch from rhui-rhel-server-rhui-rhscl-7-rpms excluded (updateinfo)
No packages needed for security; 14 packages available
3. List any available Updates
[root@tamops-rhel ~]# yum updateinfo list
Loaded plugins: langpacks, product-id, search-disabled-repos
RHSA-2021:2523 Important/Sec. bpftool-3.10.0-1062.51.1.el7.x86_64
RHSA-2021:2728 Important/Sec. bpftool-3.10.0-1062.52.2.el7.x86_64
RHSA-2021:2405 Important/Sec. dhclient-12:4.2.5-77.el7_7.1.x86_64
RHSA-2021:2405 Important/Sec. dhcp-common-12:4.2.5-77.el7_7.1.x86_64
RHSA-2021:2405 Important/Sec. dhcp-libs-12:4.2.5-77.el7_7.1.x86_64
RHSA-2021:2175 Important/Sec. glib2-2.56.1-6.el7_7.x86_64
RHSA-2021:2998 Moderate/Sec. glibc-2.17-292.el7_7.2.x86_64
RHSA-2021:2998 Moderate/Sec. glibc-common-2.17-292.el7_7.2.x86_64
RHSA-2021:2523 Important/Sec. kernel-3.10.0-1062.51.1.el7.x86_64
RHSA-2021:2728 Important/Sec. kernel-3.10.0-1062.52.2.el7.x86_64
RHSA-2021:2523 Important/Sec. kernel-tools-3.10.0-1062.51.1.el7.x86_64
RHSA-2021:2728 Important/Sec. kernel-tools-3.10.0-1062.52.2.el7.x86_64
RHSA-2021:2523 Important/Sec. kernel-tools-libs-3.10.0-1062.51.1.el7.x86_64
RHSA-2021:2728 Important/Sec. kernel-tools-libs-3.10.0-1062.52.2.el7.x86_64
RHSA-2021:2304 Important/Sec. microcode_ctl-2:2.1-53.16.el7_7.x86_64
RHSA-2021:3029 Important/Sec. microcode_ctl-2:2.1-53.18.el7_7.x86_64
RHSA-2021:2523 Important/Sec. python-perf-3.10.0-1062.51.1.el7.x86_64
RHSA-2021:2728 Important/Sec. python-perf-3.10.0-1062.52.2.el7.x86_64
RHBA-2021:2951 bugfix redhat-release-server-7.7-12.el7.x86_64
RHBA-2021:3402 bugfix redhat-release-server-7.7-13.el7.x86
4. Run yum update to update RHEL
[root@tamops-rhel ~]# yum update
- Verify release version
cat /etc/os-release
cat /etc/redhat-release
- Reboot server
reboot
Ubuntu
1. Upgrade
root@tamops-ubuntu:~# apt-get update
Hit:1 http://azure.archive.ubuntu.com/ubuntu bionic InRelease
Get:2 http://azure.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Get:3 http://azure.archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]
Get:4 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
Get:5 http://azure.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages [8570 kB]
Get:6 http://azure.archive.ubuntu.com/ubuntu bionic/universe Translation-en [4941 kB]
2. Review Security Updates against CVE Dashboard
root@tamops-ubuntu:~# apt-get upgrade -s | grep -i security
19 standard security updates
Inst login [1:4.5-1ubuntu2] (1:4.5-1ubuntu2.2 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [amd64])
Conf login (1:4.5-1ubuntu2.2 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [amd64])
Inst python-samba [2:4.7.6+dfsg~ubuntu-0ubuntu2.27] (2:4.7.6+dfsg~ubuntu-0ubuntu2.28 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [amd64]) []
Inst samba-common-bin [2:4.7.6+dfsg~ubuntu-0ubuntu2.27] (2:4.7.6+dfsg~ubuntu-0ubuntu2.28 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [amd64]) []
Inst samba-common [2:4.7.6+dfsg~ubuntu-0ubuntu2.27] (2:4.7.6+dfsg~ubuntu-0ubuntu2.28 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [all]) []
Inst samba-libs [2:4.7.6+dfsg~ubuntu-0ubuntu2.27] (2:4.7.6+dfsg~ubuntu-0ubuntu2.28 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [amd64]) []
Inst libwbclient0 [2:4.7.6+dfsg~ubuntu-0ubuntu2.27] (2:4.7.6+dfsg~ubuntu-0ubuntu2.28 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [amd64])
Inst passwd [1:4.5-1ubuntu2] (1:4.5-1ubuntu2.2 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [amd64])
Conf passwd (1:4.5-1ubuntu2.2 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [amd64])
Inst vim [2:8.0.1453-1ubuntu1.7] (2:8.0.1453-1ubuntu1.8 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [amd64]) []
Inst vim-tiny [2:8.0.1453-1ubuntu1.7] (2:8.0.1453-1ubuntu1.8 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [amd64]) []
Inst vim-runtime [2:8.0.1453-1ubuntu1.7] (2:8.0.1453-1ubuntu1.8 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [all]) []
Inst xxd [2:8.0.1453-1ubuntu1.7] (2:8.0.1453-1ubuntu1.8 Ubuntu:18.04/bionic-updates, Ubuntu:18.04/bionic-security [amd64]) []
Inst vim-common [2:8.0.1453-1ubuntu1.7] (2:8.0.1453-1ubuntu1.8 Ubuntu
3. Lists any available Updates
root@tamops-ubuntu:~# apt list --upgradable
Listing... Done
libpolkit-agent-1-0/bionic-updates,bionic-security 0.105-20ubuntu0.18.04.6 amd64 [upgradable from: 0.105-20ubuntu0.18.04.5]
libpolkit-backend-1-0/bionic-updates,bionic-security 0.105-20ubuntu0.18.04.6 amd64 [upgradable from: 0.105-20ubuntu0.18.04.5]
libpolkit-gobject-1-0/bionic-updates,bionic-security 0.105-20ubuntu0.18.04.6 amd64 [upgradable from: 0.105-20ubuntu0.18.04.5]
libwbclient0/bionic-updates,bionic-security 2:4.7.6+dfsg~ubuntu-0ubuntu2.28 amd64 [upgradable from: 2:4.7.6+dfsg~ubuntu-0ubuntu2.27]
linux-azure/bionic-updates,bionic-security 5.4.0.1068.47 amd64 [upgradable from: 5.4.0.1067.46]
linux-cloud-tools-azure/bionic-updates,bionic-security 5.4.0.1068.47
4. Update Ubuntu
root@tamops-ubuntu:~# apt-get upgrade -y
- Reboot server
reboot
Windows
PS C:\Users\tamops> ((New-Object -ComObject Microsoft.Update.Session).CreateUpdateSearcher()).Search('IsInstalled=0 and IsHidden=0').updates | Select-Object -Property Title,IsDownloaded,RebootRequired | ft -AutoSize
Title IsDownloaded RebootRequired
----- ------------ --------------
2021-01 Update for Windows Server 2019 for x64-based Systems (KB4589208) False False
2022-01 Cumulative Update Preview for .NET Framework 3.5, 4.7.2 and 4.8 for Windows Server 2019 for x64 (KB5009823) False False
Patching Troubleshooting
This section includes updates of any issues encountered during patching and how to resolve.
RHEL 6.10 not showing any patches available
RHEL 6.10 is the latest version for RHEL 6 and is End of Life and not supported - therefore there will be no available patches if previously patched to latest version.
Patching and upgrading RHEL 7 to latest version and not showing any patches available
If trying to patch and upgrade RHEL 7 to the latest version (i.e. 7.7 to 7.9) and if no patches are showing as available then the repos will need checked and updated:
[root@NSDT-DB-VM01 ~]# yum updateinfo list
Loaded plugins: langpacks, product-id, search-disabled-repos, subscription-manager
This system is not registered with an entitlement server. You can use subscription-manager to register.
updateinfo list done
If patching to the latest version remove the releasever file:
rm /etc/yum/vars/releasever
If patching to a specific higher version then update this file to the required version.
Disable non-EUS repositories:
yum repolist enabled
yum-config-manager --disable rhui-microsoft-azure-rhel7-eus
yum-config-manager --disable rhui-rhel-7-server-rhui-eus-supplementary-rpms
yum-config-manager --disable rhui-rhel-7-server-rhui-eus-optional-rpms
yum-config-manager --disable rhui-rhel-7-server-rhui-eus-rpms
Get the latest Azure RHEL 7 repository config file:
wget https://rhelimage.blob.core.windows.net/repositories/rhui-microsoft-azure-rhel7.config
Add the latest Azure RHEL 7 repositories:
yum --config=rhui-microsoft-azure-rhel7.config install rhui-azure-rhel7
Remove the disabled repos to reduce space usage:
cd /var/cache/yum/x86_64/7.7
du -sh *
rm -rf rhui-microsoft-azure-rhel7-eus
rm -rf rhui-rhel-7-server-rhui-eus-optional-rpms
rm -rf rhui-rhel-7-server-rhui-eus-rpms
rm -rf rhui-rhel-7-server-rhui-eus-supplementary-rpms
Clean up the repos and confirm patches are now available and can upgrade to latest version:
yum clean all
yum repolist enabled
yum updateinfo list
Errors
Transaction check error:
file /etc/cron.daily/rhui-update-client from install of rhui-azure-rhel7-2.2-606.noarch conflicts with file from package rhui-azure-rhel7-eus-2.2-491.noarch
Error Summary
-------------
The file might have a different title, but the fix is the same. To resolve the above delete the offending file with:
yum remove rhui-azure-rhel7-eus-2.2-491.noarch
Transaction check error:
installing package clamav-data-0.103.9-1.el7.noarch needs 17MB on the /var filesystem
Error Summary
-------------
Disk Requirements:
At least 17MB more space needed on the /var filesystem.
To clean up some disk space try the following:
cd /var/opt/microsoft/omsconfig
cat /dev/null > omsconfigdetailed.log
cat /dev/null > omsconfig.log
High CPU or memory
To see which processes are using the most CPU/Memory run
top
ps -ef |grep aide
which will return a list of the aide processes. If CPU/ Memory usage is very high try terminating some of the aide processes by taking the PID Numbers from the list and running the below
kill -9 1211 2376
where the numbers are the PIDs, replace as required.