1. Time and Time Zones 1.1 Time Standards UTC, Coordinated Universal Time, is the current time standard, counted by atomic time. GMT, Greenwich Mean Time, is the older time standard, which defines the moment the sun passes over the Royal Observatory in Greenwich, on the outskirts of London, as 12 noon.

1. Error message When pulling an image, you will occasionally run into the following error: 1 2 3 4 5 6 7 8 docker pull node:10.16-alpine 10.16-alpine: Pulling from library/node e7c96db7181b: Already exists 50958466d97a: Pulling fs layer 56174ae7ed1d: Pulling fs layer 284842a36c0d: Pulling fs layer error pulling image configuration: Get https://production.

Application configuration management is about the configuration that an application depends on at runtime, which is different from the static configuration of a project. This article is a summary drawn from real development work, offered for your reference; discussion is welcome too. 1. About Configuration Management 1.1 Terminology Configuration item A single key=value pair

Judging from the survey data, more people lean toward choosing small clusters. Below is a comparison list from the perspective of node count and node configuration. Below is a comparison of choosing a few large clusters versus many small clusters: Feature A few large clusters Many small clusters Resource utilization High Low Node management overhead Low High Resource scaling range Large Small Resource scheduling range Large Small Efficiency of inter-application communication High Low Cluster operations difficulty High Low Cluster version diversity Low High Blast radius Large Small Below is a comparison of choosing a few high-spec nodes versus many low-spec nodes:

1. SSH Connection direction: Master actively connects to Agent Requirements: Master can connect directly to Agent over SSH The SSHD service is running on Agent Jenkins has the SSH Credentials Plugin and the SSH Build Agents plugin installed 2. JNLP Connection direction: Agent actively connects to Master Requirements: Agent can reach Master Agent needs a JVM environment to run Master needs to expose port 50000 (the default) for Agent communication Port 50000 is the service port of the Jenkins Master; no other service program needs to be run for it.