ursuad

Kafka Topics

List existing topics

bin/kafka-topics.sh --zookeeper localhost:2181 --list

Describe a topic

bin/kafka-topics.sh --zookeeper localhost:2181 --describe --topic mytopic

Purge a topic

bin/kafka-topics.sh --zookeeper localhost:2181 --alter --topic mytopic --config retention.ms=1000

... wait a minute ...

moneytoo

### No longer needed as of nginx-1.13.6-1.el7_4.ngx.x86_64.rpm from nginx.org
### it was compiled against OpenSSL 1.0.2 from CentoOS 7.4 so it supports ALPN (HTTP2 works)

yum -y groupinstall 'Development Tools'
yum -y install wget openssl-devel libxml2-devel libxslt-devel gd-devel perl-ExtUtils-Embed GeoIP-devel rpmdevtools

OPENSSL="openssl-1.0.2l"
NGINX_VERSION="1.13.5-1"
NJS_VERSION="1.13.5.0.1.13-1"

bennylope

How to Add a Watermark to Video

FFMPEG filters provide a powerful way to programmatically enhance or alter videos, and it’s fairly simple to add a watermark to a video using the overlay filter. The easiest way to install ffmpeg is to download a pre-built binary for your specific platform. Then you don’t have to worry about including and installing all the right dependencies and codecs you will be using.

Once you have ffmpeg installed, adding a watermark is as easy as passing your existing source through an overlay filter like so:

ffmpeg -i test.mp4 -i watermark.png -filter_complex "overlay=10:10" test1.mp4

Basically, we’re passing in the original video, and an overlay image as inputs, then passing it through the filter, and saving the output as test1.mp4.

leommoore

#MongoDB 3.2.x Security

##Network Ports The standard ports used by mongo are:

Process	Role	Default Port

leommoore

MongoDB 3.2.x Logging

The main log file is the mongod.log. You can specify the log file location when you are starting the mongod process but if you have installed on Ubuntu from a package then you log file will normally be located in /var/log/mongodb/mongod.log.

You can tail the log file using:

tail -f /var/log/mongodb/mongod.log

From the Mongo shell you can also view the log file using:

show logs

leommoore

#MongoDB 3.2.x Sharding Sharding is used when the database is too large to run on a single server and you need to spread the load across multiple servers. The name itself refers to the breaking (sharding) of the data into seperate groups of data which will reside on different servers.

##Configuration Server Start the server on your server (myserver0)

mongod --configsvr --dbpath /data

On myserver1 start the shard giving the configuration server as the --configdb option

leommoore

#MongoDB 3.2.x Replica Sets on AWS EC2 A MongoDB replica set provides a mechanism to allow for a reliable database services. The basic replica set consists of three servers, a primary, a secondary and an arbitrator. The primary and secondary both hold a copy of the data. The arbitrator is normally a low spec server which just monitors the other servers and help with the failover process. In production, there can be more than three servers.

To setup mongo as a replica set on Amazon Web Services EC2 you need to first setup a security group with ssh on port 22 and mongodb on port 27017. You then need to create three servers. Select Ubuntu 14.04 LTS x64 and a micro (or bigger depending on your database size, ideally you should have enough memory to match your database size) instance for the primary and secondary and a nano instance for the arbitrator.

##Adjust the File System on each Server The operating system by default will update the last access time on a file. In a high data throughput database application

leommoore

#MongoDB 3.2.x

##Install MongoDB To install MongoDB on ubuntu from precompiled version.

wget https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-ubuntu1404-3.2.5.tgz
gzip -d mongodb-linux-x86_64-ubuntu1404-3.2.5.tgz
tar -xvf mongodb-linux-x86_64-ubuntu1404-3.2.5.tar

Then check put what is in the bin directory

leommoore

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

MichaelKreil

# Stream a video
ffmpeg -re -i video.avi -vf "scale=40:ih*40/iw, crop=40:16" -f rawvideo -vcodec rawvideo -sws_flags bilinear -pix_fmt rgb24 - > /dev/udp/matelight.cbrp3.c-base.org/1337

# Loop a gif
ffmpeg -re -ignore_loop 0 -i image.gif -vf "scale=40:ih*40/iw, crop=40:16" -f rawvideo -vcodec rawvideo -sws_flags bilinear -pix_fmt rgb24 - > /dev/udp/matelight.cbrp3.c-base.org/1337

# Stream webcam
# Mac
ffmpeg -re -f avfoundation -r 30 -s 1280x720 -i "0" -vf "scale=40:ih*40/iw, crop=40:16, pp=autolevels:f, eq=1.5" -f rawvideo -vcodec rawvideo -sws_flags bilinear -pix_fmt rgb24 - > /dev/udp/matelight.cbrp3.c-base.org/1337