Upgrade Strategies: An Introduction for IaC

When upgrading infrastructure, especially in cloud computing environments, various deployment strategies can be employed to ensure minimal downtime and maintain service-level agreements. Traditional methods of upgrading individual resources manually are impractical in large-scale cloud environments. Instead, strategies such as blue-green deployments, canary deployments, and rolling deployments are used. Blue-green deployments involve creating a parallel environment to test upgrades before switching traffic over, ensuring stability before decommissioning the old system. Canary deployments gradually introduce new infrastructure to a small portion of traffic to detect potential issues under real-world conditions before a full rollout. Rolling deployments replace system elements one at a time, ensuring each new instance is fully operational before proceeding. These strategies, adapted from application deployment practices, offer more efficient and reliable ways to manage infrastructure updates without disrupting service.