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Install K8S on VM and spring boot integration.

Installation Environment Vmware Workstation pro  It is recommended to use the  snapshot  to store the state of each installation stage to avoid installation failures and causing the installation to start from scratch. Ubuntu 22.04 windows 11 Hardware settings  create 3 VM: 4 cores and 4G memory and 100G capacity Before installing K8s (All use the root user) set host: 192.168.47.135 master 192.168.47.131 node1 192.168.47.132 node2 set root ssh connection: sudo su - echo "PermitRootLogin yes" >> /etc/ssh/sshd_config systemctl restart sshd sudo passwd ssh-keygen for i in {master,node1,node2}; do  ssh-copy-id root@$i; done set Ipvs and conf  create conf file: for i in {master,node1,node2}; do ssh root@$i 'cat << EOF > /etc/modules-load.d/containerd.conf overlay br_netfilter EOF'; done execute conf: for i in {master,node1,node2}; do ssh root@$i 'modprobe overlay;modprobe br_netfilter;'; done create 99-kubernetes-cri.conf file: for i in {maste...
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GC Basic Algorithm

Theory

Most GCs follow the theory of generational collection, which is based on the following two:
  • Week generational hypothesis: Most of the objects are short-living.
  • Strong generational hypothesis: The more times an object survives GC, the harder it is to die.

Mark-Sweep

  • After the marking phase has been completed all space occupied by unvisited objects is considered free and can thus be reused to allocate new objects.
  • There may exist plenty of free regions but if no single region is large enough to accommodate the allocation, the allocation is still going to fail.

Mark-Copy

  • To avoid excessive fragmentation, it splits the space into two parts and copies the surviving objects into empty parts.
  • The disadvantage is the need for one more memory region, which should be large enough to accommodate survived objects.

Mark-Compact

  • Like mark-copy, it doesn't require another space to copy but a more complex operation to move the object.

Reachability analysis

First, GC defines some specific objects as Garbage Collection Roots. Examples of such GC roots are:
  • Local variable and input parameters of the currently executing methods
  • Active threads
  • Static field of the loaded classes
  • JNI references
Next, GC traverses the whole object graph in your memory, starting from those Garbage Collection Roots and following references from the roots to other objects, e.g. instance fields. Every object the GC visits is marked as alive.

When the marking phase finishes, every live object is marked. All other objects are thus unreachable from the GC roots, implying that your application cannot use the unreachable objects anymore. Such objects are considered garbage and GC should get rid of them.



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Install K8S on VM and spring boot integration.

Installation Environment Vmware Workstation pro  It is recommended to use the  snapshot  to store the state of each installation stage to avoid installation failures and causing the installation to start from scratch. Ubuntu 22.04 windows 11 Hardware settings  create 3 VM: 4 cores and 4G memory and 100G capacity Before installing K8s (All use the root user) set host: 192.168.47.135 master 192.168.47.131 node1 192.168.47.132 node2 set root ssh connection: sudo su - echo "PermitRootLogin yes" >> /etc/ssh/sshd_config systemctl restart sshd sudo passwd ssh-keygen for i in {master,node1,node2}; do  ssh-copy-id root@$i; done set Ipvs and conf  create conf file: for i in {master,node1,node2}; do ssh root@$i 'cat << EOF > /etc/modules-load.d/containerd.conf overlay br_netfilter EOF'; done execute conf: for i in {master,node1,node2}; do ssh root@$i 'modprobe overlay;modprobe br_netfilter;'; done create 99-kubernetes-cri.conf file: for i in {maste...
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SOLID

SOLID is the fundamental and core principle of OOP. Single-Responsibility Principle High cohesion: A module preferably has only one business logic. Low coupling:   The different modules work independently and are connected by simple protocols to minimize side effects. Open-Closed Principle Open for extension:  It is easy to extend new functions with existing code. Close for modification:  Do not modify existing classes to ensure stable functions. Liskov-Substitution Principle A superclass should be replaceable with objects of its subclasses without breaking the application. Interface-Segregation Principle Clients only depend on the interfaces they need, don't use the "big" interface to contain everything. Dependence-Inversion Principle The program should depend upon abstractions, not concretions. reference: https://en.wikipedia.org/wiki/SOLID https://blog.knoldus.com/what-is-liskov-substitution-principle-lsp-with-real-world-examples/ https://github.com/hollischuang/toBeTo...
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Annotation

Table of contents [ hide ] Design pattern Annotations are an implementation of the decorator design pattern. The decorator pattern is a design pattern that allows behavior to be added to an individual object, dynamically, without affecting the behavior of other objects from the same class. Annotations in Java Annotations, a form of metadata, provide data about a program that is not part of the program itself. Annotations have no direct effect on the operation of the code they annotate. Annotations have a number of uses: Information for the compiler:  Annotations can be used by the compiler to detect errors or suppress warnings Compile-time and deployment-time processing:  Software tools can process annotation information to generate code, XML files, and so forth. Runtime processing:   Some annotations are available to be examined at runtime. Annotations in Spring Spring uses annotations extensively as a core feature, especially Spring AOP, and almost all the fu...
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