2017年10月

about DNS cache

如何查看系统 DNScache 的 TTL (time to live). 如下,dig 命令的 hostname 之后就是 DNS server 返回的 TTL

 eric$ dig tianxiaohui.com

;; ANSWER SECTION:
tianxiaohui.com.    10  IN  A   118.184.11.30

如何查看浏览器 DNS TTL 时间:
chrome : chrome://net-internals/#dns
https://stackoverflow.com/questions/36917513/how-long-google-chrome-and-firefox-cache-dns-records

java 里面如何设置 DNS TTL:
https://docs.oracle.com/javase/7/docs/technotes/guides/net/properties.html

参考:
https://apple.stackexchange.com/questions/93949/how-long-does-the-dns-cache-last-in-mac-os-x
http://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/java-dg-jvm-ttl.html

docker command cheat sheet

to check docker installed or not

$ docker -v
$ docker info

how to start docker daemon

###1. Add the user to the docker group.
$ sudo usermod -aG docker $(whoami)
###2. Log out and log back in to ensure docker runs with correct permissions.
###3. Start docker.
$ sudo service docker start

$ docker login localhost:8080 //docker login [OPTIONS: -u, -p] [SERVER]
$ docker logout localhost:8080

$ docker commit container_id repo:tag //get container id from docker ps -l -q
$ docker commit -m 'message' -a 'admin@tianxiaohui.com' container_id repo:tag

$ docker build -t="repo/name:tag" .
$ docker build -t="repo/name" /path/to/file
$ docker build --no-cache -t="repo/name" .

$ docker images -a //list all images
$ docker images [REPOSITORY[:TAG]] //list bye repo and tag
$ docker images --no-trunc //list full image id

$ docker history image_id

$ docker rmi image_id

$ docker run [OPTIONS] IMAGE [COMMAND] [ARG...]
$ docker run -i -t 8dbd9e392a96 /bin/bash
$ docker run --name eric -d -p 8080:80 image_id
$ docker run --restart=always image_id
$ docker run --restart=on-failure:5 image_id //non-zero exit, max retry 5

$ docker start container_id
$ docker restart container_id
$ docker stop container_id
$ docker kill container_id

$ docker attach container_id

$ docker exec -i -t 8dbd9e392a96 /bin/bash
$ docker exec -d container_id apt-get update

$ docker ps -a
$ docker ps -l n

$ docker rm [container_id or container_name]
$ docker rm -f docker ps -a -q

$ docker logs -f container_id
$ docker logs -f --tail 30 container_id

$ docker top container_id

$ docker stats container_id1 ...

$ docker inspect container_id
$ docker inspect --format '{{.NetworkSetting.IPAddress}}' container_id

$ docker port container_id

in linux, all the docker info are in folder : /var/lib/docker/

关于 Java Cert, keystore

keytool -list -v -keystore $JAVA_HOME/jre/lib/security/cacerts Java default password: changeit

openssl s_client -connect google.com:443

https://en.wikipedia.org/wiki/Keystore
http://docs.oracle.com/javase/6/docs/technotes/tools/solaris/keytool.html