Installing Draco-ngsi from sources

Installing Draco

Cloning `fiware-Draco`

Start by cloning the GitHub repository:

    $ git clone https://github.com/ging/nifi.git
    $ cd fiware-Draco
    $ git checkout <branch>

<branch> should be typically a stable release branch, e.g. release/2.0.0, but could also be master (synchronized with the latest release) or develop (contains the latest not stable changes).

From this point the way to install Draco is exactly the same as NiFi so, we will use the same step as the Official NiFi Documentation.

Linux Operating System Configuration

NOTE: If you are building on Linux, consider these best practices. Typical Linux defaults are not necessarily well tuned for the needs of an IO intensive application like NiFi. For all of these areas, your distribution's requirements may vary. Use these sections as advice, but consult your distribution-specific documentation for how best to achieve these recommendations.

Maximum File Handles

NiFi will at any one time potentially have a very large number of file handles open. Increase the limits by editing '/etc/security/limits.conf' to add something like.

*  hard  nofile  50000
*  soft  nofile  50000

Maximum Forked Processes

NiFi may be configured to generate a significant number of threads. To increase the allowable number edit '/etc/security/limits.conf'

hard nproc 10000
soft nproc 10000

And your distribution may require an edit to /etc/security/limits.d/90-nproc.conf by adding

soft nproc 10000

Increase the number of TCP socket ports available

This is particularly important if your flow will be setting up and tearing down a large number of sockets in small period of time.

sudo sysctl -w net.ipv4.ip_local_port_range="10000 65000"

Set how long sockets stay in a TIMED_WAIT state when closed

You don't want your sockets to sit and linger too long given that you want to be able to quickly setup and teardown new sockets. It is a good idea to read more about it but to adjust do something like

sudo sysctl -w net.ipv4.netfilter.ip_conntrack_tcp_timeout_time_wait="1"

Tell Linux you never want NiFi to swap

Swapping is fantastic for some applications. It isn't good for something like NiFi that always wants to be running. To tell Linux you'd like swapping off you can edit '/etc/sysctl.conf' to add the following line

vm.swappiness = 0

Disable partition atime

For the partitions handling the various NiFi repos turn off things like atime. Doing so can cause a surprising bump in throughput. Edit the /etc/fstab file and for the partition(s) of interest add the noatime option.

Build steps

You need a recent Java 8 (or newer) JDK for the 1.x NiFi line. Older Java 8 (such as 1.8.0_31) is known to fail with some unit tests, ensure to use the most recent version. The 0.x line works on Java 7 or newer.
You need Apache Maven 3.1.0 or newer.
You need a recent git client for the 1.x NiFi line.
Ensure your MAVEN_OPTS provides sufficient memory. Some build steps are fairly memory intensive
- These settings have worked well MAVEN_OPTS="-Xms1024m -Xmx3076m -XX:MaxPermSize=256m"
Build the entire code base. In the root dir of the source tree run mvn -T C2.0 clean install -Pinclude-grpc
- You can tweak the maven build settings as you like but the previous command will execute with 2 threads per core.
- You can omit the '-Pinclude-grpc' if you're not on a platform that it supports.

Now you should have a fully functioning build off the latest codebase.

NOTE: During development it is not necessary to build the entire code base. Typically, in case of a NAR bundle change you can build only the particular bundle followed by running mvn -T C2.0 clean install -Ddir-only in nifi-assembly.

Running the application

WARNING

Without any configuration, the application will run on port 8080 and does not require any credentials to modify the flow. This means of running Apache NiFi should be used only for development/testing and in an environment where only connections from trusted computers and users can connect to port 8080. Using iptables to allow only localhost connections to 8080 is a good start, but on systems with multiple (potentially untrusted) users, also not a sufficient protection.

Decompress and launch

Running the above build will create a tar.gz (and zip) file in ./nifi-assembly/target. This tar.gz should contain the full application. Decompressing the tar.gz should make a directory for you containing several other directories. conf contains application configuration, bin contains scripts for launching the application. On linux and OSX, NiFi can be run using bin/nifi.sh <command> where <command> is one of:

start: starts NiFi in the background
stop: stops NiFi that is running in the background
status: provides the current status of NiFi
run: runs NiFi in the foreground and waits to receive a Ctrl-C, which then shuts down NiFi.
install: (available in Linux only, not OSX): installs NiFi as a service that can then be controlled via service nifi start, service nifi stop, service nifi status.

For Windows users, the following scripts exist in the bin directory:

run-nifi.bat: runs NiFi in the foreground and waits to receive a Ctrl-C, which then shuts down NiFi
status-nifi.bat: provides the current status of NiFi

The configuration that is to be used when launching NiFi, such as Java heap size, the user to run as, which Java command to use, etc. are configurable via the conf/bootstrap.conf file.

The entire concept of how the application will integrate to a given OS and run as an enduring service is something we're working hard on and would appreciate ideas for. The user experience needs to be excellent.

With the default settings you can point a web browser at https://localhost:8443/nifi/

Logging is configured by default to log to `./logs/nifi-app.logv. The following log message should indicate the web UI is ready for use:

2014-12-09 00:42:03,540 INFO [main] org.apache.nifi.web.server.JettyServer NiFi has started. The UI is available at the following URLs:

Installing Draco-ngsi from sources