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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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Deadlocks

 A set of the blocked processes each holding some resources and waiting to acquire a resource held by another process in the set.

Necessary conditions

All four conditions must hold for possible deadlock:
  • Mutual exclusion: 
    • Only 1 process at a time can use a resource.
  • Hold and wait:
    • A process holding some resources is waiting for another resource
  • No preemption:
    • A resource can be only released by a process voluntarily.
  • Circular wait:
    • There exists a set {P0,P1…} of waiting processes such that
      • P0 -> P1 -> P2 …..Pn -> P0

Handling Deadlocks

  • Ensure the system will never enter a deadlock state.
    • Deadlock prevention: ensure that at least one of the 4 necessary conditions cannot hold.
    • Deadlock avoidance: dynamically examines the resources allocation state before allocation.
  • Allow to enter a deadlock state and then recover.
    • Deadlock detection.
    • Deadlock recovery.
  • Ignore the problem and pretend that deadlock never occurs in the system.
    • Use by most operating systems, including UNIX…

Avoidance algorithms

  • A single instance of the resource type.
    • Resource-allocation graph(RAG) algorithm based on circle detection.
  • Multiple instances of the resource type.
    • Banker's algorithm is based on safe sequence detection.

Deadlock Detection

Single instance of each resource type.
  • Convert request/assignment edges into wait-for graph
  • Deadlock exists if there is a cycle in the wait-for graph

Deadlock Recovery

  • Process termination.
  • Resource preemption.

reference:
https://www.amazon.com/-/zh_TW/Operating-System-Concepts-Abraham-Silberschatz/dp/1119800366/ref=sr_1_1?keywords=Operating-System-Concepts&qid=1669538704&s=books&sr=1-1

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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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