StepUpDevOps
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@StepUpDevOps
Sharing simplified tech concepts on DevOps! Follow for easy-to-digest insights on Linux, Containers, Cloud, Kubernetes, CI/CD, IaC
Blue-Green Deployment Pattern Explained. Renowned for "zero downtime", blue-green deployment involves maintaining two identical production environments, called "blue" and "green". At any given time, only one environment is live (let's say blue), serving all production traffic. When a new version of software is ready, it's deployed to the inactive environment (green). After comprehensive testing without affecting live traffic, users are transitioned to the green environment, which becomes the live environment, while the blue environment becomes idle, ready for the next update. This minimizes downtime and reduces the risk of deployment failures. If an issue is discovered after switching environments, it's relatively easy to switch back. The main challenge is the cost and complexity of managing two environments. So how can blue-green deployment be implemented? 1) Set up two identical environments: Ensure you have two environments that mirror each other. 2) Deploy the new version to the inactive environment 3) Test extensively: Conduct comprehensive testing in the inactive environment to ensure everything functions correctly. 4) Switch traffic: Once satisfied, redirect user traffic from the active environment to the inactive environment. The state of the environments switch. 5) Monitor and roll back if necessary: Monitor the now active environment and be prepared to switch back to previous environment if issues are detected. Blue-green deployment is particularly beneficial when zero downtime, quick rollback capabilities, thorough pre-deployment testing, and a seamless user experience are top priorities. It’s an excellent choice for high-traffic applications, complex systems, and industries with stringent compliance requirements. ~~ Thank you to our partner Kickresume who keeps our content free to the community. Did you know you can turn your LinkedIn into a resume with one click? Check it out: drp.li/linkedin-to-re…
Linux Boot Process Illustrated The diagram below shows the steps. Step 1 - When we turn on the power, BIOS (Basic Input/Output System) or UEFI (Unified Extensible Firmware Interface) firmware is loaded from non-volatile memory, and executes POST (Power On Self Test). Step 2 - BIOS/UEFI detects the devices connected to the system, including CPU, RAM, and storage. Step 3 - Choose a booting device to boot the OS from. This can be the hard drive, the network server, or CD ROM. Step 4 - BIOS/UEFI runs the boot loader (GRUB), which provides a menu to choose the OS or the kernel functions. Step 5 - After the kernel is ready, we now switch to the user space. The kernel starts up systemd as the first user-space process, which manages the processes and services, probes all remaining hardware, mounts filesystems, and runs a desktop environment. Step 6 - systemd activates the default. target unit by default when the system boots. Other analysis units are executed as well. Step 7 - The system runs a set of startup scripts and configure the environment. Step 8 - The users are presented with a login window. The system is now ready. – Subscribe to our weekly newsletter to get a Free System Design PDF (158 pages): bit.ly/3KCnWXq
