1. Migrating Infrastructure Classic Workloads to Oracle Cloud Infrastructure
  2. Review the Oracle Cloud Infrastructure Compute Classic Architecture

2 Review the Oracle Cloud Infrastructure Compute Classic Architecture

Before you begin a migration, it is critical that you review the current Oracle Cloud Infrastructure Compute Classic architecture and fully understand the artifacts of the environment and how they relate to each other. It is also important to your specific application requirements and the context of the migration.

For example, compile a list of all applications that you want to migrate to the Oracle Cloud Infrastructure environment. Consider where each application currently resides (on-prem, Oracle Cloud Infrastructure Compute Classic, other cloud, etc.). Plan for you migration based on your specific applications and their network, database, VM, block storage, HA, and DR considerations.

General Considerations

The following table describes the general considerations migrating to Oracle Cloud Infrastructure.

Category Considerations Notes

General
  • Customer technical expertise
  • Timing and downtime expectations
  • Business constraints

Setting expectations for a migration project is critical. Depending on the characteristics of the source environment, the downtime can be considerable, so it's important to make plans for the preparation, the actual migration, and for validation of the new environment before cutover.

Environment Information
  • Development
  • Test
  • Production

Knowing the purpose of the environment can help in any required architecture redesign, and can help determine downtime requirements.

Financial Account Information

Current subscription type:

  • Non-metered
  • Metered (traditional)
  • Government/Public Sector
  • Universal Credits

Make sure you have migrated your Oracle Cloud Infrastructure Compute Classic account to the new Universal Credits subscription model. This migration must be performed before making the physical workload move. Contact your Sales Representative for more information.

Data Region Location
  • Current data region/data center
  • Availability of Oracle Cloud Infrastructure data center

When migrating from Oracle Cloud Infrastructure Compute Classic to Oracle Cloud Infrastructure, the data center and data region are critical in determining how easy or difficult the migration process is. The data region can determine the connection types available between the Oracle Cloud Infrastructure Compute Classic shared network or IP network and the Oracle Cloud Infrastructure VCN.

Services used
  • IaaS Only
  • IaaS and PaaS
  • Lift and shift applications
    • Apps Unlimited
    • Fusion Middleware

Identifying the main applications and services running within an environment helps to determine the most appropriate migration strategy for each workload.

Network Considerations

The following table describes the network considerations for migrating to Oracle Cloud Infrastructure.

Category Considerations

General network requirements
  • Shared network usage
  • Number of IP networks
  • Number of external IPs
  • Bandwidth requirements
  • Load Balancer information
  • Outbound proxy for external Internet access
  • Communication between data centers
  • DNS usage

Network security
  • Security policies that exist in this environment
  • Security rules, security lists (Shared network)
  • ACLs, Virtual NIC Sets, and IP Prefix Sets (IP Network)
  • Additional security features needed beyond layer-3/4 filtering
  • Additional filtering needed (for example, layer-7)

The configuration of security rules is especially important and can introduce a layer of complexity to a migration project. It's important to understand that there is not necessarily a 1-to-1 mapping of these features from the Oracle Cloud Infrastructure Compute Classic network to the VCN on Oracle Cloud Infrastructure.

Oracle Cloud Infrastructure Compute Classic to Oracle Cloud Infrastructure Network Connection

  • Ashburn or London options
  • Other options to consider

When migrating from Oracle Cloud Infrastructure Compute Classic to Oracle Cloud Infrastructure, the data center and data region are critical in determining how easy or difficult the migration will be. The data region can determine the connection types available between the Oracle Cloud Infrastructure Compute Classic shared network or IP network and the Oracle Cloud Infrastructure VCN. This connection is used primarily for moving the workloads, data, and other artifacts from your Oracle Cloud Infrastructure Compute Classic environment to your Oracle Cloud Infrastructure environment.

On-Premise to Oracle Cloud connection
  • FastConnect Classic
  • VPN (Corente)
  • VPN as a Service (VPNaaS)

Database Considerations

The following table describes the database considerations for migrating to Oracle Cloud Infrastructure.

Category Considerations

General
  • Number of databases to migrate
  • Purpose of each database
  • Dependencies (what applications depend on each database)
  • Average size of each database

Oracle Databases
  • Type of Database deployment: Oracle Database Classic Cloud Service or on-premises software installed on a VM?
  • Version and Edition of each database

Third-party Databases
  • Brand, version and edition of each third-party database

Migration Method
  • Are there any restrictions that would prevent the use of DataGuard as the primary tool for migrating the data?
  • What is the backup method and schedule for each database

Virtual Machine Considerations

The following table describes the virtual machine considerations for migrating to Oracle Cloud Infrastructure.

Question Notes
How is access to the instance secured? For example: SSH for Linux instances, WinRM or Remote Desktop for Windows instances.
Is there a bastion host? For accessing this instance, a best practice is to configure a bastion (jump) host.
How is the system patched? Are systems patched after initial provisioning?
Is there a way to audit the fleet of VM's for patches? How to tell which VMs need additional patches? Especially CVE patches.
Is malware / anti-virus installed? Which anti-virus vendor?
How are system level logs captured? Syslogs for Unix. Event logs for Windows. Ideally connect to a log analytics system (Splunk, ELK, Graylog, ...)
Is the image hardened? Review CIS (https://www.cisecurity.org/cis-benchmarks/) benchmarks for hardening systems.
What monitoring of the system is in place? At a minimum CPU / memory / disk should be monitored. A better solution would be to alert based on these metrics.The best solution would be to provide a mechanism for auto-scaling.
Is there a firewall running on this instance? Local firewall setting may affect remote access independent of any network security rule.
Does the system sync time using NTP? Verify the NTP servers are accessible from Oracle Cloud Infrastructure, or consider using the Oracle Cloud Infrastructure NTP service.
How are the attached disks backed up? Verify there is a plan for backup / restore.
Are fault domains being leveraged? Verify that fault domains are being considered as compute instances are provisioned.

Block Storage Considerations

The following table describes the block storage considerations for Oracle Cloud Infrastructure Compute Classic to Oracle Cloud Infrastructure migration.

Question Notes

Verify performance (IOPS, latency, throughput) is reasonable for your workload.

Use fio or Cloud Harmony benchmark to gather benchmark numbers. For details, see https://docs.cloud.oracle.com/iaas/Content/Block/Concepts/blockvolumeperformance.htm.

Verify block volume backup plan.

Ideally this should be automated or use policy based backups.

When using iSCSI, enable CHAP authentication.

For security, always enable CHAP authentication for iSCSI devices.

Custom Image Considerations

The following table describes the custom image considerations for Oracle Cloud Infrastructure Compute Classic to Oracle Cloud Infrastructure migration.

Question Notes

Be aware of limitations (size, reserved IP addresses, Windows export...) custom images

Documented at: https://docs.cloud.oracle.com/iaas/Content/Compute/Tasks/managingcustomimages.htm

Since images can be shared across regions, upload images only as needed for startup time.

Trade off management of images versus startup time for a new instance.

Application-Level Disaster Recovery Considerations

The following list describes the application-level disaster recovery considerations for Oracle Cloud Infrastructure Compute Classic to Oracle Cloud Infrastructure migration.

  • Is the application accessed via a DNS FQDN or by IP address directly?

  • Will failover between prod and DR be accomplished by making DNS changes?

  • Are there any other IP requirements between DR, prod and any other environments or are these largely undefined/nonexistent (such as using the same IP addressing for both prod and DR, etc.)?