Failed to start Docker daemon

Docker daemon failed to start after run yum update -y command on CentOS 7.

Get into the Docker VM

When using Docker Desktop for Mac and Windows | Docker - https://www.docker.com/products/docker-desktop, you’re actually using a tiny (custom) Alpine Linux running in a special xhyve VM on macOS or Windows. There’s so much cool stuff happening, you’re meant to forget it’s still running on a Linux kernel.

Docker Compose FAQs

ImportError: No module named ‘requests.packages.urllib3’

1
2
3
4

# CentOS 7.x
$ docker-compose up
...
ImportError: No module named 'requests.packages.urllib3'

Install specific version of requests.

1
2
3

$ sudo pip install requests urllib3 pyOpenSSL --force --upgrade

$ sudo pip install --upgrade --force-reinstall 'requests==2.6.0'

References

References

[1] Microservices in Go: REST APIs (Part 4) - OpenAPI 3 and Swagger UI - https://mariocarrion.com/2021/05/02/golang-microservices-rest-api-openapi3-swagger-ui.html

[2] REST Servers in Go: Part 4 - using OpenAPI and Swagger - Eli Bendersky’s website - https://eli.thegreenplace.net/2021/rest-servers-in-go-part-4-using-openapi-and-swagger/

[3] Go, Swagger, and Open API. Documenting Go REST services with… | by Pagis | May, 2021 | Level Up Coding - https://levelup.gitconnected.com/go-swagger-and-open-api-e6b6ea4ce48f

Swagger Open API Specification 2.0 and 3.0 in Go | by Kecci Kun | Medium - https://kecci.medium.com/swagger-open-api-specification-2-0-and-3-0-in-go-c1f05b51a595

deepmap/oapi-codegen: Generate Go client and server boilerplate from OpenAPI 3 specifications - https://github.com/deepmap/oapi-codegen

getkin/kin-openapi: OpenAPI 3.0 implementation for Go (parsing, converting, validation, and more) - https://github.com/getkin/kin-openapi

go-swagger/go-swagger: Swagger 2.0 implementation for go - https://github.com/go-swagger/go-swagger

Swagger 2.0 | Primer · GitBook - https://goswagger.io/

swaggo/swag: Automatically generate RESTful API documentation with Swagger 2.0 for Go. - https://github.com/swaggo/swag

FAQs - Deisel

Diesel is a Safe, Extensible ORM and Query Builder for Rust.

Bitnami Redis with Docker and Docker Compose

Bitnami makes it easy to get your favorite open source software up and running on any platform, including your laptop, Kubernetes and all the major clouds. In addition to popular community offerings, Bitnami, now part of VMware, provides IT organizations with an enterprise offering that is secure, compliant, continuously maintained and customizable to your organizational policies.

Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache, and message broker. Redis provides data structures such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps, hyperloglogs, geospatial indexes, and streams. Redis has built-in replication, Lua scripting, LRU eviction, transactions, and different levels of on-disk persistence, and provides high availability via Redis Sentinel and automatic partitioning with Redis Cluster.

docker history

Show the history of an image

Prerequisites

• Docker

  Docker is a tool to build safer, share wider, run faster: New updates to our product subscriptions.

  See Empowering App Development for Developers | Docker - https://www.docker.com/
  to learn more.

Usage

1

$ docker history [OPTIONS] IMAGE

For example uses of this command, refer to the examples section below.

Options

1
2
3
4
5

Name, shorthand	Default	Description
--format		Pretty-print images using a Go template
--human , -H	true	Print sizes and dates in human readable format
--no-trunc		Don't truncate output
--quiet , -q		Only show image IDs

Examples

To see how the docker:latest image was built:

1
2
3
4

$ docker history docker
(nop) ENV LC_ALL=C.UTF-8            0 B
(nop) ADD jessie.tar.xz in /        121 MB
(nop) MAINTAINER Tianon Gravi <ad   0 B

To see how the docker:apache image was added to a container’s base image:

1
2
3

$ docker history docker:scm
(nop) ADD file:1fd8d7f9f6557cafc7   373.7 MB
(nop) MAINTAINER Lokesh Mandvekar   0 B

Format the output

The formatting option (--format) will pretty-prints history output using a Go template.

Valid placeholders for the Go template are listed below:

1
2
3
4
5
6
7

Placeholder	Description
.ID	Image ID
.CreatedSince	Elapsed time since the image was created if --human=true, otherwise timestamp of when image was created
.CreatedAt	Timestamp of when image was created
.CreatedBy	Command that was used to create the image
.Size	Image disk size
.Comment	Comment for image

When using the --format option, the history command will either output the data exactly as the template declares or, when using the table directive, will include column headers as well.

The following example uses a template without headers and outputs the ID and CreatedSince entries separated by a colon (:) for the busybox image:

1
2

$ docker history --format "{{.ID}}: {{.CreatedSince}}" busybox
: 4 weeks ago

References

[1] docker history | Docker Documentation - https://docs.docker.com/engine/reference/commandline/history/

[2] Empowering App Development for Developers | Docker - https://www.docker.com/

Nginx Header Security

Here’s how to add various HTTP response header to your Nginx site for better website security protection.

errors

error is a interface, here is its definition:

1
2
3

type error interface {
    Error() string
}

redis-rb

A Ruby client that tries to match Redis’ API one-to-one, while still providing an idiomatic interface.