Many businesses fail to consider potential problems with IP addresses when moving to the cloud. Learn how cloud service providers handle address assignment to start.
In the process of moving workloads from a local data centre to the public cloud, businesses frequently ignore IP address problems.
The IP address ranges and availability are normally constrained by your cloud provider and the usage of your cloud instance, thus the address your workload uses in the public cloud differs typically from the address it uses on-premises and is frequently dynamic.
For instance, it would be ideal for the public cloud instance to adopt the in-house service’s IP address when migrating an internal service, such as a web server, to a public cloud, such as Amazon Web Services. But, this just doesn’t happen. Instead, a limited number of internal and external IP addresses, including virtual IP addresses for services and instances, are available from public cloud providers and are used to apply workloads. An on-premises IP address cannot easily be made to route correctly to a cloud provider by users.
The fact that IP addresses are often assigned dynamically compounds the problems with IP addresses. When a workload restarts after an instance has stopped, the cloud IP address may have changed. The difficulty of all of this increases when other workloads require access to the recently relocated workload. For instance, if the newly relocated workload is a database or another back-end system that other workloads depend on, those other services are now inaccessible since they can no longer find the relocated service at its new IP address.
But, there are a few methods that help ease this transition and avoid major IP address issues.
First, users in public clouds typically have some control over the IP address assigned to their instances. In order to guarantee that the address won’t change while the instance reboots, cloud providers frequently offer static IP assignments for customer-facing services like a web server. Even if the final address is unlikely to match your initial on-premises IP address, you can choose an IP address and rest assured that it won’t change throughout the instance.
There are, nevertheless, a number of strategies that can make this move easier and prevent serious IP address problems.
First, the IP address given to users’ instances in public clouds is usually something they may influence. For instance, some customer-facing services, like a web server, need to have a static IP address, and cloud providers typically provide for static IP assignments to ensure that the address won’t change as the instance reboots. You can choose an IP address and be sure that it won’t change for the duration of the instance, even though the final address is unlikely to match your original on-premises IP address.
