Infojunk July 2018

Better than VNC and TeamViewer – NoMachine and the NX protocol

The NX protocol is basicaly a successor to the X protocol and very nyce for Streaming. NoMachine implements that and is a better VNC with video streaming and a nice alternative to TeamViewer with good cross-platform capabilities. Also keyboard and mouse works cross-plattform without any problems. This is an issue with most alternatives to TeamViewer. Yet TeamViewer still is number #1 for me.

https://www.nomachine.com/

In-depth:

In 2001, the compression and transport protocol NX was created to improve on the performance of the native X display protocol to the point that it could be usable over a slow link such as a dial-up modem. It wrapped remote connections in聽SSH聽sessions for encryption.

The NX scheme was derived from that of DXPC 鈥 the Differential X Protocol Compressor project. NX 1.x was released to the general public on February 14, 2003, the final version of ‘NX’ being 3.5. The last update of 3.5 was in 2012.

The core compression technology up until NX 3.5 was made available to the community under the GNU聽GPL2聽license whilst other components such as the NX Server and NX Client programs were proprietary.

In 2009, Google made a freely available Open Source GPL2 version of the server called Neatx. Other open source variants of NoMachine’s NX are also available (see below).

Starting in 2013, with the release of version 4.0, NX technology became closed source.

https://en.wikipedia.org/wiki/NX_technology

 

Anti-Patterns and Mental Downers

Most known about anti-patterns. This is now more about the psychological side.

It happened to me that I thought there must be a release chat and tried to gather information about it, asked in the company chat 鈥 no one answers. Finally I was added two month late. Today I recognized I was forget when gettign acces to some Shared Googe Drive folder. But everyone thought I know about the information that was shared within there. Because it is taken as obvious.

Perfectionism聽is good for your work? Nope! The psychological definition says 鈥渟uffering from not beeing enough鈥, 鈥渦nmeetable high standards鈥.

It鈥檚 even more a downer when you are in an complex environment that always asks 鈥渨hen it will be ready?鈥 鈥淚 can鈥檛 imagine that this is such a big problem!鈥.

The opposite is聽conscientiousness. Do you work well, gather information you need, communicate, be gentle. Care about quality of human interactions, quality of you work and then the product will also be good.

A聽false consensus聽effect or聽pluralistic ignorance聽very common among developers.

But聽most important is to know about cognitive biases聽and that聽others are humans, too:

Always look on the bright side of life! Evolve! I think that this is important!

Using confd and consul for config management

Consul is used in clouds as key/value store to holds configs just like etcd, Zookeeper, AWS SSM etc. Additionaly consul can provide a DNS server (service discovery).

In this tutorials we wanna test out, how we can create configs for our applications in development stack by local confd run. This will take configuration templates build configs by information provided by consul.

The idea is that we just provide templates to our applications and by these templates generate our configurations from key/values stored on consul.

Advantages

Applications repositories defined the config-format
No more versionless configs (yet we need to get enviornments straight!)

And hence it鈥檚 consul we鈥檙e one step closer to cloud-readiness

Example

Install confd

We wanna use local confd 鈥 one file 鈥 thanks to golang and easy install:

sudo wget -O /usr/local/bin/confd https://github.com/kelseyhightower/confd/releases/download/v0.16.0/confd-0.16.0-linux-amd64
sudo chmod a+x /usr/local/bin/confd

Run dockerized consul

Open up a new terminal and run consul kv exposed to localhost by port 8550 (in memory only!):

docker run --rm --name=dev-consul -p 8500:8500 -e CONSUL_BIND_INTERFACE=eth0 consul
Store some values
curl -X PUT -d 'db.example.com' http://localhost:8500/v1/kv/myapp/database/url
curl -X PUT -d 'Charles Brown' http://localhost:8500/v1/kv/myapp/database/user

# This is how you get values
curl -f http://localhost:8500/v1/kv/myapp/database/url?raw
curl -f http://localhost:8500/v1/kv/myapp/database/user?raw
curl -f http://localhost:8500/v1/kv/myapp/database/non-existent?raw
Add some config files to our working directory

conf.d/myconfig.toml

[template]
src = "myconfig.conf.tmpl"
dest = "myconfig.conf"
keys = [
"/myapp/database/url",
"/myapp/database/user",
]

templates/myconfig.conf.tmpl

[myconfig]
database_url = {{getv "/myapp/database/url"}}
database_user = {{getv "/myapp/database/user"}}
We now have folling directory structure:

Directory Structure

鈹溾攢鈹 conf.d
鈹 鈹斺攢鈹 myconfig.toml
鈹斺攢鈹 templates
鈹斺攢鈹 myconfig.conf.tmpl

Create our configs by templates

$ confd -onetime -backend consul -node 127.0.0.1:8500 -confdir $(pwd)/ 
2018-06-07T13:42:41+02:00 refpad-16 confd[7689]: INFO Backend set to consul
2018-06-07T13:42:41+02:00 refpad-16 confd[7689]: INFO Starting confd
2018-06-07T13:42:41+02:00 refpad-16 confd[7689]: INFO Backend source(s) set to 127.0.0.1:8500
2018-06-07T13:42:41+02:00 refpad-16 confd[7689]: INFO Target config myconfig.conf out of sync
2018-06-07T13:42:41+02:00 refpad-16 confd[7689]: INFO Target config myconfig.conf has been updated
$ cat myconfig.conf 
[myconfig]
database_url = db.example.com
database_user = Charles Brown
$ touch xxx >> myconfig.conf
$ confd -onetime -backend consul -node 127.0.0.1:8500 -confdir $(pwd)/ 
2018-06-07T13:44:49+02:00 refpad-16 confd[8151]: INFO Backend set to consul
2018-06-07T13:44:49+02:00 refpad-16 confd[8151]: INFO Starting confd
2018-06-07T13:44:49+02:00 refpad-16 confd[8151]: INFO Backend source(s) set to 127.0.0.1:8500
2018-06-07T13:44:49+02:00 refpad-16 confd[8151]: INFO myconfig.conf has md5sum 7a30123886573e65b3c9d31a4e1c1abf should be e919f09ba963caad1051c212c5ca9453
2018-06-07T13:44:49+02:00 refpad-16 confd[8151]: INFO Target config myconfig.conf out of sync
2018-06-07T13:44:49+02:00 refpad-16 confd[8151]: INFO Target config myconfig.conf has been updated

Summary

There are some more advances examples on consul GitHub. We aim for an infrastructure that is able to reconfigure while running. Notifications. Monitoring. Service-Descovery. These topics are not covered here.

Also there are better tools like remco or consul template that support multiple backend sources and do secret stores and better auth.Just dig into it.

Further readings
– How Should I Get Application Configuration into my Docker Containers?
– DigitalOcean: How To Use Confd and Etcd to Dynamically Reconfigure Services
– Consul security model and Hashicorp鈥檚 Vault