CLI-Notes.md

Why I prefer CLI over UI ?

• CLI tools are Composable using pipes (great old school example http://www.youtube.com/watch?v=tc4ROCJYbm0&t=5m32s)
• Great for automation and batch processing
• Fewer mouse clicks. Can go futher using only keyboard
• Avoid cluky UIs especially over poor connections
• I'm insulated from UI changes
• Easier to debug as they are often more verbose than the UI

The DC/OS CLI (https://dcos.io/docs/1.7/usage/cli/)

Intro

• The CLI for your data center
• Open source,implementation in python https://github.com/dcos/dcos-cli
• Extensible - you can write your own subcommands (e.g. https://github.com/mesosphere/dcos-helloworld )

Basics

• Installable on Linux, Mac and Windows clients (https://dcos.io/docs/1.7/usage/cli/install/)
• Starting 0.4.5 Cli team started shipping binaries (https://github.com/dcos/dcos-cli/releases)
• Has subcommands for doing basic operations on your cluster
• Installing some packages adds more functionality using new subcommands
• Very userful Help docs, can be invoked using --help on top or subcommand level

Hidden gems

• Default config file lives in ~/.dcos/dcos.toml. %USERPROFILE%\.dcos\dcos.toml on Windows
• Code for subcommands lives in ~/.dcos/subcommands
• DCOS_CONFIG environment variable can be used to override the default config file.
• If you want to debug a CLI error use dcos --debug --log-level=debug to get very verbose output

Tips & Tricks

Useful tools

• jq for pretty printing and processing JSON https://stedolan.github.io/jq/
• HTTPie human friendly curl alternative https://github.com/jkbrzt/httpie

Hitting API endpints in an authenticated cluster

curl --header "Authorization:curl --header token=$(dcos config show core.dcos_acs_token)" http://52.21.51.123/mesos/master/state-summary

curl --header "Authorization:curl --header token=$(dcos config show core.dcos_acs_token)" http://52.21.51.123/marathon/v2/leader

curl -skSL -H "Authorization: token=$(dcos config show core.dcos_acs_token)" $(dcos config show core.dcos_url)/mesos/master/slaves | grep slave_public | wc

Using CLI for Marathon

• Deploy and update Marathon apps

  dcos marathon app add tomcat.json

  dcos marathon app update /tomcat < tomcat.json

• Deploy app on MoM instance instead of root marathon

  dcos config set marathon.url $(dcos config show core.dcos_url)/service/marathon-user

  dcos marathon app add nginx.json

Debugging using the CLI

dcos package install cassandra
dcos task
dcos task ls cassandra
dcos task log cassandra stderr

Doing fancy stuff using dcos node ssh (https://dcos.io/docs/1.7/administration/sshcluster/)

• SSH into nodes for debugging

dcos node ssh --leader --master-proxy

• Find out which node a service is runnig on

dcos task --json | jq --raw-output '.[] | select(.name == "tomcat") | .slave_id'
dcos node ssh --option StrictHostKeyChecking=no --option LogLevel=quiet --master-proxy --mesos-id=$(dcos task --json | jq --raw-output '.[] | select(.name == "tomcat") | .slave_id') "curl -s ifconfig.co" 2>/dev/null

• Find out public IPs of all Public agents

dcos node --json | jq --raw-output '.[] | select(.reserved_resources.slave_public != null) | .id'
for id in $(dcos node --json | jq --raw-output '.[] | select(.reserved_resources.slave_public != null) | .id'); do dcos node ssh --option StrictHostKeyChecking=no --option LogLevel=quiet --master-proxy --mesos-id=$id "curl -s ifconfig.co" ; done

Multi-Cluster CLI

• First approach

cp ~/.dcos/dcos.toml ~/.dcos/alpha.toml
DCOS_CONFIG=~/.dcos/alpha.toml dcos config set core.dcos_url http://52.38.178.200
alias alpha='DCOS_CONFIG=~/.dcos/alpha.toml dcos'
alpha auth login
alpha marathon app list 

• Better approach In .bashrc put the following snippet :

dcos ()
{
    # find current working directory
    local cwd=$(pwd)
    # path for config file in current directory 
    local config_file="${cwd}/dcos.toml"
    # find the location for dcos CLI binary
    # \which makes sure we use unaliased which
    local dcos_binary="$(\which dcos)"
    #check if config file exists in current directory
    if [ -f "$config_file" ]
    then
        # use config file in current directory
        DCOS_CONFIG="${config_file}" "$dcos_binary" "$@"
    else
        # use default config file 
        "$dcos_binary" "$@"
    fi
}

alias dcos='dcos'

mkdir -p clusters/{alpha,beta,gamma}
for dir in clusters/{alpha,beta,gamma}; do cp ~/.dcos/dcos.toml $dir; done
cd clusters/alpha
dcos config set core.dcos_url http://52.38.178.200
dcos auth login