Author: clsung

[docker] Multi-stage builds

Consider the following scenario: you are going to rolling update your cluster, and it turns out your network bandwidth is limited for some reason and size of built docker image is not small enough. What’s worse, every instance of cluster will need to pull the docker image before start-up… Read More

CoreOS remove early-docker since 1284.0.0

It happens the docker daemon wasn’t alive when I login to the console.

After review the release document, it seems early-docker.target should be remove in all related target.

Ref: CoreOS Release 1284.0

2016-08-25

Update salt from 2015.5.3 to 2016.3.2

When reading salt’s source code, it seems we have a ‘source_hash_update’ option on “archive.extracted”, however when I added so, salt complains:

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Developing with consul on Macbook

For development use, we need to have consul running on localhost. When using a Macbook (Air), we need to specify the “-bind=0.0.0.0” and “-client=0.0.0.0” in order to have programs (tests) access to the consul agent in the container:  Read More

重整 Exif 資料

多想幾天,可以不用重新發明輪子。 :p
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Install docker on Centos 7

Perform a yum search docker, we can see two docker available:

docker.x86_64 : Automates deployment of containerized applications
docker-io.x86_64 : Automates deployment of containerized applications

Well, at least for today, the docker.x86_64, which is mentioned in , is still 0.11. So please install the docker-io.x86_64, which is 1.0.0-1.el7.

Updated 20140829: there’s more up-to-date repo for docker.

Updated 20150111: it seems the repo is out of managed now. And official repo is upgraded to 1.3.2. Thus the official repo is recommended now.

% # just use original one
% # curl -O https://copr.fedoraproject.org/coprs/goldmann/docker-io/repo/epel-7/goldmann-docker-io-epel-7.repo
% # sudo mv goldmann-docker-io-epel-7.repo
% # yum update
% # yum install docker-io
% sudo service docker start
Redirecting to /bin/systemctl start docker.service

EPEL 7 for Centos 7

To install EPEL-7

Also, enable it by default, edit /etc/yum.repos.d/remi.repo and set ‘enable=1’ under section of [remi] and [remi-

Install GNU gcc 4.8.2 on CentOS 6.4

Install pre-requirements:

Download and extract gcc 4.8.2 source tar ball:

Build and install:

 % make; make install<

Crop image in golang

In python, for cropping  image I use PIL. However the dependencies of PIL is huge, also need to install some lib*-dev packages.

So I choose go to crop images:

Usage:

% go run crop.go large.jpeg thumbna

Create file with random string in python

#!/usr/bin/env python
import string
import random

out_file = 'text_file.txt'
file_size = 1024 * 1024

rands = lambda x: ''.join(random.choice(string.letters + string.digits) for x in xrange(x))
with open(out_file, 'w') as f:
f.write(rands(file_size))