The result could be the unexpected termination of the Java process. If the Java Virtual Machine does not take configured cgroup limits into account, it might risk trying to consume more resources than the operating system is willing to provide to it. When Java processes are deployed in such an environment, cgroup limits might be set for the deployed process. The Linux kernel ensures that when resource limits are in place via the cgroup, no process goes beyond those limits (at least not for extended periods of time). Container engine options, in turn, set resource limits via the Linux cgroup pseudo-filesystem. Those limits translate into options that are passed to the container engine when containers are deployed. Kubernetes and many other popular cloud orchestration systems let deployments limit container resources via CPU and memory quotas. OpenJDK container awareness has been available in Java 17 and Java 11 since their respective general availability (GA) releases, and in Java 8u starting with update 8u202. These resource limits affect, for example, the garbage collection (GC) algorithm selected by the JVM, the default size of the heap, the sizes of thread pools, and how default parallelism is determined for ForkJoinPool. OpenJDK detects whether certain resource quotas are in place when running in a container and, if so, uses those bounds for its operation. As of this writing, OpenJDK 17, OpenJDK 11.0.16+ and OpenJDK 8u372+ are the only long-term support releases that support both cgroups v1 and cgroups v2 configurations. OpenJDK's container awareness detection uses Linux's control group (cgroup) filesystem to detect enforced resource quotas. In this article, you'll learn why container awareness is useful, what has changed recently in that area of OpenJDK, and what diagnostic options are available to help developers gain insight into how the JVM determines settings. By container awareness, we mean that OpenJDK detects when it is running inside a container. OpenJDK has been aware of Linux containers (such as Docker and Podman, as well as container orchestration frameworks such as Kubernetes) for some time.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |