d-mongodb/README.md

# d-mongodb

This repo contains files for creating a MongoDB Docker container.

## TL; DR

Run `make`.

## MongoDB Docker Image

This Docker container is based on the image from 
[frodenas on github](https://github.com/frodenas/docker-mongodb/).
The main change is that we are adding a build script and a run script,
and a few tweaks to the Dockerfile.

To get the MongoDB authentication credentials for the docker container,
check the logs using Docker - the credentials are printed to the logs.

```
$ docker logs inspiring_malachai
```

## MongoDB Docker Image

Two scripts do the building and running of the Docker image.
Don't call them directly - use the Makefile.

```
$ make
```

This should bind port 27017 from the host machine 
to port 27017 on the container.

## Building the Docker Container

To build the Docker container, use the Makefile.

The `build_mongodb.sh` script will do the following:
* Build the Docker container using the Dockerfile

## Running the Docker Container

To run the Docker container, use the Makefile.

This script ask you to open the firewall of the machine
running the Docker container to expose the 
container's service to the outside world.

The `run_mongodb.sh` script will do the following:
* Mount /wifi in the host machine to /wifi in the container
* Map port X on the host machine to port X in the container (X is specified as the first command line argument)

## Container Actions

The Dockerfile will do the following:
* Set up MongoDB aptitude repository for MongoDB 3.0
* Mount local `/opt/mongodb` to container `/data/db`

## Test MongoDB

The `test/` directory contains two Python scripts to test out the MongoDB:

```
$ cd test/
$ python test_mongo_insert.py
$ python test_mongo_retrieve.py
```

Run them in that order.

## Notes

* Different versions of MongoDB are located at the github repo [frodenas/docker-mongodb](https://github.com/frodenas/docker-mongodb/branches).

### User Credentials

The first time you run your container,  a new user `mongo` with all privileges will be created with a random password.
To get the password, check the logs of the container by running:

```
docker logs <CONTAINER_ID>
```

You will see an output like the following:

```
========================================================================
MongoDB User: "mongo"
MongoDB Password: "ZMUgiS3O1kJH1ec5"
MongoDB Database: "admin"
MongoDB Role: "dbAdminAnyDatabase"
========================================================================
```

If you want to preset credentials instead of a random generated ones, you can set the following environment variables:

* `MONGODB_USERNAME` to set a specific username
* `MONGODB_PASSWORD` to set a specific password

On this example we will preset our custom username and password:

```
$ docker run -d \
    --name mongodb \
    -p 27017:27017 \
    -e MONGODB_USERNAME=myusername \
    -e MONGODB_PASSWORD=mypassword \
    frodenas/mongodb
```

### Databases

If you want to create a database at container's boot time, you can set the following environment variables:

* `MONGODB_DBNAME` to create a database
* `MONGODB_ROLE` to grant the user a role to the database (by default `dbOwner`)

On this example we will preset our custom username and password and we will create a database with the default role:

```
$ docker run -d \
    --name mongodb \
    -p 27017:27017 \
    -e MONGODB_USERNAME=myusername \
    -e MONGODB_PASSWORD=mypassword \
    -e MONGODB_DBNAME=mydb \
    frodenas/mongodb
```

### Extra arguments

When you run the container, it will start the 
MongoDB server without any arguments. 
If you want to pass any arguments,
just add them to the `run` command:

```
$ docker run \
	-d --name mongodb \
	-p 27017:27017 \
	mongodb \
	--smallfiles
```

### Persistent data

MongoDB will store data in `/data`.
Map `/data` to the host to keep data persistent.

```
$ mkdir -p /tmp/mongodb

$ docker run -d \
    --name mongodb \
    -p 27017:27017 \
    -v /tmp/mongodb:/data \
    mongodb
```



---


## Some Big Stupid Problems

A big huge waste of time working out some
big huge stupid problems that were
extremely difficult to track down. End lessons:

1. Lots of problems w/ things that would
be set up the exact same way, then show different 
problems. That was a sign there might be issues
with the Docker container being able to write to 
the files. 

2. The data directory I was using (and have seen 
online in several places) is `/data/db` but this 
was straight up wrong and caused me to lose all 
my data. It should have been `/data`.

3. Checked and had to fix permissions of the directory
being shared as the data directory. Mongo user.

4. The lock file issues were resolved by turning 
on journaling with the --jorurnal flag, but issues
still persisted.

5. Running interactively kept showing connection problems
with localhost port 27017, these actually turned out to
be file repair issues. So I found the repair flag.

6. After adding the repair step, had to work out 
the order. The repair step has to be called first
and separate from everything in the first run
script.

7. Fix the mongodb scripts to use journaling
and repair stuff and not NOT use journaling, etc.


## Startup Script

Call the included startup script 
from `/etc/rc.local` as a regular
user as follows:

```
su charles -c '/path/to/script.sh
```