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...
Basic concept
- The idea of multiprogramming:
- Keep several processes in memory. Every time one process has to wait, another process takes over the use of the CPU.
- CPU-I/O burst cycle:
- Process execution consists of a cycle of CPU execution and I/O wait(i.e., CPU burst and I/O burst).
- Generally, there is a large number of short CPU bursts and a small number of long CPU bursts
- An I/O-bound program would typically have many very short CPU bursts.
- A CPU-bound program might have a few long CPU bursts.
CPU scheduler
Select from the ready queue to execute(I.e allocates an APU for the selected process)
CPU scheduling decision may take place when a process:
- Switch from running to waiting state.
- Switch from running to ready state.
- Switch from waiting to ready.
- Terminates.
- Non-preemptive scheduling:
- Scheduling under 1 and 4(no choice in terms of scheduling).
- The process keeps the CPU until it is terminated or switched to the waiting state.
- Preemptive scheduling:
- Scheduling under all cases.
Scheduling Criteria
- CPU utilization
- Theoretically: 0% ~100%
- Real system: 40%(light)~90%(heavy)
- Throughput
- Number of completed processes per time unit
- Turnaround time
- Submission ~ completion
- Waiting time
- Total waiting time in the ready queue
- Response time
- Submission ~ the first response is produced
Algorithms
- First-Come, First-Served(FCFS) scheduling.
- Shortest-job-First(SJF) scheduling.
- Approximate shortest-job-first(SJF):
- SJF-difficulty: no way to know the length of the next CPU burst.
- Approximate SJF: the next burst can be predicted as an exponential average of the measured length of the previous CPU burst.
- Priority scheduling.
- Problem: starvation(low-priority processes never execute).
- Solution: aging(as time progresses increases the priority of processes.
- Round-Robin scheduling.
- Multilevel queue scheduling.
- Multilevel feedback queue scheduling.
Evaluation methods
- Deterministic modeling - takes a particular predetermined workload and defines the performance of each algorithm for that workload, cannot be generalized.
- Queueing model - mathematical analysis.
- Simulation - random-number generator or trace tapes for workload generation.
- Implementation - the only completely accurate algorithm evaluation.
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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