OpenShift on Azure - Custom DNS
If you are using RedHat OpenShift on Azure as your container platform, you are most likely using Azure DNS to resolve names of your cluster nodes – at least when you deployed it using the ARM-Template provided by Microsoft with Azure as the OpenShift cloud provider instead of an “Bare-Metal” installation on Azure VMs without an cloud provider config.
All the pods running on your compute nodes will have the same DNS servers as the host, because it’s the default inheritance in Kubernetes.
Servers on Azure receive their IP configuration from the Azure DHCP-service. This results in configurations on the server - on Linux, the file /etc/resolve.conf gets filled with the custom DNS servers configured in your VNET.
If you run the command:
hostname -f
you will get the hostname and the Azure internal DNS-Name, something like:
server1.tido0jwesfsdflksjkl7485wi4392jf.gx.internal.cloudapp.net
This means, your pods will not be able to use the DNS-suffix of your local domain to resolve DNS-names, Assuming you want to use your local domain for DNS, you need to modify the file
sudo vi /etc/sysconfig/network-scripts/ifcfg-eth0
and add the property DOMAIN=yourdomain.local
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=dhcp
TYPE=Ethernet
USERCTL=no
PEERDNS=yes
IPV6INIT=no
NM_CONTROLLED=yes
DHCP_HOSTNAME=server1
DOMAIN=yourdomain.local
After restarting the server, your server has the wanted fqdn
hostname -f
server1.yourdomain.local
Of course you should apply these changes using Ansible to all nodes in your cluster and you must update the inventory file because now your hosts need to use the new fqdn.
Office 365 Tenant to Tenant Migration Fundamentals
Business changes, acquisitions, divestments, and corporate reorganizations often result in the need to merge companies or divisions. Today, a large number of companies already use Office 365 services, so an important step for IT is to ensure seamless collaboration and provide centralized management for the various divisions / companies.
Post Azure Monitor Alerts in Microsoft Teams Channel
This topic is not new and quite frankly, it is hard to believe this is still not integrated yet, but at some point, during your cloud journey, you probably want to send monitoring alerts to a certain Teams channel. Even though this is functionality is available for plenty of other services, Azure Monitor still lacks this.