Hodor v4
Several times in the past I’ve created a script called ‘hodor’. This week created the fourth version of the script.
Hodor is a script to emit a test vm for me to do something with. Expected usage:
$ hodor herpderp
Hodor! Making vm
VM ready! ssh root@herpderp.hodor.nibz.science
In past iterations, hodor was written against HP cloud in bash. Then written against HP cloud, IBM cloud, and vexxhost using the shade library in python. Then written again against vexxhost but using bash.
Version four of hodor is written in bash against the IBM Cloud Softlayer vsi infrastructure. It makes heavy use of the bluemix (bx for short) utility. It has dns integration and ssh key integration.
To get started I bought the throwaway domain name nibz.science and registered it via gandi. Gandi, by the way, is a great registrar and recently updated their user experience to be much better. After everything went through, I set the NS records to point at SoftLayer.
$: dig -t ns nibz.science
; <<>> DiG 9.10.3-P4-Ubuntu <<>> -t ns nibz.science
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57026
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;nibz.science. IN NS
;; ANSWER SECTION:
nibz.science. IN NS ns2.softlayer.com.
nibz.science. IN NS ns1.softlayer.com.
;; Query time: 2 msec
;; SERVER: 127.0.1.1#53(127.0.1.1)
;; WHEN: Fri Jan 19 23:45:33 CST 2018
;; MSG SIZE rcvd: 90
Once that was done, I setup the domain in SL. CLI dns management in IBM Cloud/Softlayer is clunky but effective.
$: bx sl dns zone-create nibz.science
OK
Zone nibz.science was created.
$:
From there (after a little time) adding records was easy.
$: bx sl dns record-add nibz.science throwaway A 127.0.0.1 --ttl 3600
OK
Created resource record under zone nibz.science: ID=106702065, type=A, record=throwaway, data=127.0.0.1, ttl=3600.
With DNS particulars setup, I just had to write a script to boot a vm.
The bx sl vs command is how you do this. (That expands out to ‘bluemix softlayer virtual-server’ if anyone was curious.) This is another clunky utility, but I don’t blame it too much, there are just a ton of dimensions to virtual server creation and that all comes together in the create command. One of the reasons for me creating hodor is that I don’t want to know or think about ram, datacenter, ubuntu version, etc. I just want a latest ubuntu with enough resources to be able to screw around and I want it now.
$ bx sl vs create -H $name -D hodor.nibz.science -c 8 -m 16384 -d dal09 -o UBUNTU_LATEST --disk 100 --key $my_key_id --force --wait 3600
Unpacking this a bit. The name and domain here are more or less what you’d expect. 8 vcpu cores and 16 gigs of ram is big enough that if I need more than that I probably can take the time to create a server more manually. dal09 is one of softlayer’s datacenters. The --key option refers to the id of an ssh key added with the bx sl security command. --force creates the server without asking you to confirm. --wait 3600 turns the create operation into a blocking command with a timeout of an hour. In testing, vms took between 3 and 4 minutes to come up.
This command returns some info about the server, including it’s id. I grab that id and run the details command to get the ip.
$: bx sl vs detail 48197835
Name Value
ID 48197835
guid 0a0babd8-49f3-44d8-b6b4-0c629b7d7eaf
hostname gethype-1
domain hodor.nibalizer.science
fqdn gethype-1.hodor.nibalizer.science
status Active
state Running
datacenter dal09
os Ubuntu
os version 16.04-64 Minimal for VSI
cpu cores 8
memory 16384
public ip 169.54.244.9
private ip 10.142.169.37
private network false
private cpu false
created 2018-01-20T04:27:42Z
updated 2018-01-20T04:30:53Z
note
vlans type number ID
PUBLIC 846 2248345
PRIVATE 824 2248347
With the ip and id, I’m able to set the dns record. These generally populate through pretty darn quickly, so long as you don’t ask too soon and end up caching a negative response.
The script in whole:
$: cat hodor.sh
#!/bin/bash
echo "please have sl set up"
bx sl vs list | grep hodor
name=$1
if [ -z $name ]; then
echo NEED NAME HODOR
fi
echo "Starting " `date`
id=$(bx sl vs create -H $name -D hodor.nibz.science -c 8 -m 16384 -d dal09 -o UBUNTU_LATEST --disk 100 --key 1063573 --force --wait 3600 | grep ID | awk '{print $NF}')
ip=$(bx sl vs detail 48196973 | grep 'public ip'| awk '{print $NF}')
bluemix sl dns record-add nibz.science $name.hodor A $ip --ttl 3600
echo "Ending " `date`
echo "SL id is" $id
echo "hostname is" $name.hodor.nibz.science
echo "ssh root@${ip}"
What isn’t reflected in this work so far, is automatic cleanup or caching. The holy grail, in my mind, is Puppet’s vmpooler. The pooler keeps a quota of hot, already prepared and functional vms around, so that checking one out is effectively instant. It also has the concept of leases, by default they’ll be cleaned up 24 hours after checkout unless the user presses a button or hits an api to extend the lease.
I’d love to build something like that (vmpooler is too tied to vmware to try to just write another driver) but for me, saving just a few minutes isn’t worth the expenditure of having unused vms sitting around just in case I decide I do want them.
However, I could build a cleanup daemon that would delete hodor vms 24 hours after creation. In past use of the script these throwaway test vms tend to pile up and sit around.
$: ./hodor.sh jenkins
please have sl set up
Starting Sat Jan 20 00:04:47 CST 2018
OK
Created resource record under zone nibz.science: ID=106709115, type=A, record=jenkins.hodor, data=169.54.244.2, ttl=3600.
Ending Sat Jan 20 00:08:34 CST 2018
SL id is 48200667
hostname is jenkins.hodor.nibz.science
ssh root@169.54.244.2
References:
- SSH Keys in Softlayer: https://knowledgelayer.softlayer.com/procedure/ssh-keys-0
- VM Pooler: https://github.com/puppetlabs/vmpooler
