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## Setup of Development/Test Data Management System on Multiple Nodes
In a typical setup, it is necessary to install the Data Mangement System on multiple nodes. Centralizining overall long term data storage for instance would argue that the Data Storage Service on one, or possibly a small set of, server(s). On a given experiemnt, it may be necessary to have more than one DAQ node to deal with different detectors. This document will describe a two node setup. These nodes will be
* The data-storage node. This will provide the data storage service, a central database (which stores information on users, experiments, and beamline deployments) and Web Portal that allows some management of the sytem.
* The exp-station node. This will provide the _daq_, _proc_ and _cat_ web services which will manage moving data from the collection system to the storage system, processing the data as needed and cataloging steps in storage and processing.
### Computer setup.
In production at APS we are using RedHat Enterprise Linux 7 on all machines. For development we are using either RHEL 7 (centrally managed by IT group) machines or CentOS 7 machines (user managed and installed as a VirtualBox VM). When installing, we are typically selecting a devolopment workstation configuration as a starting point for work. In addition to this, a number of requirements have been put together and can be found [here](https://confluence.aps.anl.gov/display/DMGT/DM+Station+System+Requirements). When using VirtualBox, once the OS has completed this system can be cloned to make additional machines with the same configuration. It is therefore recommended to keep a copy of the VM to use as a starting point to repeat the work done.
The typical multiple node VM setup uses two network interfaces. These interfaces are configured in the VirtualBox setup. The first network interface is configured as a generic NAT connection which will allow the VM to access the public network in order to facilitate support tool downloads during installation. This would allow also access to facility resources if it is required. This could be used to extend the __DM__ system to connect to facility resources such as the aps\_db\_web\_service which provides access to systems such as the APS Experiment Safety Assment Form (ESAF), System and Beamline Scheduling System (BSS). The second network interface is configured as a 'Host-only Adapter' on the 'vboxnet0' network. This interface will be used to set up the systems to communicate with each other.
The __DM__ System installation process will use the 'hostname -f' command to get the system name. The host name is used by the __DM__ system when configuring services to make them available 'publicly' on the 'Host-only Adapter' network. This makes services available to the other VMs running on the 'vboxnet0' network. In order for the to recieve names for each system during network setup, the hostname must be set for each system. The system hostname on a CentOS system can be set with the hostnamectl command. In a multiple node environment VMs will also need some form of name resolution for the VM nodes in the system. This can be acheived by adding node entries in /etc/hosts file.
The DM installation process uses scp to transfer some files (such as Certificate Authority files) from one node to another during the setup process. To facilitate this process, ssh-keys should be generated for the different nodes and be copied into the authorized key files on the data-storage node. On both of these systems the following command will generate a set of RSA key files.
> ssh-keygen
When prompted for location for these files accept the default ($HOME/.ssh/id\_rsa). When prompted for a password, press the enter return for no password. To copy the public key into the authorized file use the _ssh-copy-id_ command. On both machines use:
> ssh-copy-id -i ~/.ssh/id\_rsa.pub dmadmin@data-storage
The DM System will use a number of different ports to provide services. As a root user run _firewall-config_. Add _permanent_ ports for services shown in the table below.
data-storge ports
| Port Number | Service |
| --- | --- |
| 22236 | DM Storage |
| 8181 | DM Administrative Portal |
exp-station ports
| Port Number | Service |
| 33336 | DM DAQ Service |
| 44436 | DM Cataloging Service |
| 55536 | DM Processing Service |
| 26017 | Mongo DB Server |
| 18182 | Mongo Express Application, localhost |
| 8182 | Nginx Server |
### Support Tools Installation
Before installation of the APS Data Management System a number of tools need to be installed on the server nodes. The __DM__ system depends on tools such as Java, Python, Postgresql, MongoDB, ZeroMQ, etc. A set of scripts have been established which will download, build (when necessary) and install these tools for use with the __DM__ system. While it is possible to install most of these tools using more conventional means (e.g. RPM on Linux) the install scripts provided here builds and installs these tools specifically for use with the __DM__ system.
For the purposes of this tutorial, we will are creating two nodes which will contain different piesces of the __DM__. One node will be referred to as the data-storage node this will contain the data storage web service and the Postgresql database which conatains the user database. The second node will b reffered to as the exp-station node. This node will provide the cat web service (a catalog of the stored data), the daq web service (provides a way to move collected data) and the proc web service (provides a means to process data).
These scripts can be found in the APS git repository at:
https://git.aps.anl.gov/DM/dm-support.git](https://git.aps.anl.gov/DM/dm-support.git)
* Select an account (such as dmadmin) which will build, install and manage the __DM__ system.
* Select a parent location to install the system and create a subdirectory __DM__ to contain the __DM__ system and the support tools. We will refer to this directory in future sections as DM\_INSTALL\_DIR
* Install a copy of the code from the _support_ git repository in DM\_INSTALL\_DIR. This can be done in a variety of ways (3rd an 4th should be the most common)
- Grab a zip file from the APS Gitlab website (from URLs above) and unzip the file.
- Clone the repositories directly into DM\_INSTALL\_DIR (basically like cloning a forked repo shown below)
- Fork the repository following the fork link in the top right of the project page and then clone the repository as shown below. The example shown clones the dm-support repository into a directory __support__ and the __DM__ repository into a directory __dev__. In each case the clone is pulled from the user _USERNAME_'s fork of the repository.
> git clone https://git.aps.anl.gov/_USERNAME_/dm-support.git __support__ (Assumes forking repository)
* Change directory to the _support_ directory
> cd support
We will install support tools needed by the data-storage node. Again these tools will support the data storage service, a central database (which stores information on users, experiments, and beamline deployments) and Web Portal that allows some management of the sytem. For these services, this step will install postgresql, openjdk, ant, payara, python and a number of needed python modules.
* Run the command `./sbin/install_support_ds.sh`. This installation will take some time to complete as this will download, compile and configure a number of key tools. NOTE: to later wipe out this step of the install run `./sbin/clean_support_all.sh`.
* As this script runs, you will be prompted to provide passwords for the master and admin accounts for the Payara web server. Choose appropriate passwords & record these for later use. These will be used to manage the Payara server, which will provide a portal for managing some parts of the DM.
##### On exp-station node
Similar to the data-storage node, we will install support tools for the experiment station node. These tools will support the daq, proc & cat web services. This will facilitate managing file transfers during or after acquisition, processing data after collection and managing experiment meta-data. To support this this will download & install Python 2 and a number of associated modules and Python 3 and the same modules. Note, in the near future this should be just Python 3 versions.
* Run the command `./sbin/install_support_daq.sh`. This will take a some time as it downloads & compiles from source. NOTE: Again, to later wipe out this step of the install run `./sbin/clean_support_all.sh`.
### Data Management component installation
Once again, we are installing two different systems, each with different parts of the system to provide different features on each. Also, scripts have been developed to install and configure the components of the system. These scripts can be found at
[https://git.aps.anl.gov/DM/dm.git](https://git.aps.anl.gov/DM/dm.git)
The installation scripts for the DM System assume a particular directory structure. The contents of this repository should be cloned in the DM\_INSTALL\_DIR into a directory corresponding to a version tag. This allows the system to be updated in a way that allows updating the system in operation with a new versioned directory. Initially, and as the system is updated, a symbolic link called _production_, in DM\_INSTALL\_DIR, should be directed to the version tagged directory of _dm_. Similarly, if it is discovered that fallback is necessary, then the link will be moved back to an older version. An example of this, is shown in the image below.
A stepped instruction for this, assuming as with the support module a fork of the _dm_ repository has been forked by a user, follows. These steps should be followed on both _data-storage_ and _exp-station_ nodes.
* Change directory to DM\_INSTALL\_DIR
* clone the forked repository into a version_tagged directory
> git clone https://git.aps.anl.gov/_USERNAME_/dm.git dm\_version\_tag
* create a link of the cloned directory to _production_
> ln -s dm\_version\_tag production
#### data-storage Node Installation
This node will be responsible for providing the data storage web service, the postgresql database (which stores information on users, experiments, and beamline deployments), and the payara web server (provides portal for management).
To install _dm_ compnents for the data-storage node
* cd DM\_INSTALL\_DIR/production
* edit etc/dm.deploy.conf to change DM\_CA\_HOST to data-storage
* ./sbin/install\_dm\_deploy\_data\_station.sh
- This deploy process will install components and prompt for user input as necessary. Prompts will ask for a number of system passwords, some existing and some being set by this process, node names for the DS web service node and file locations. These include
- __postgres__ admin account - This will be used to manage the postgres itself. Each developer can set this to a unique value.
- __dm__ db management account - This will be for mananging the 'dm' database in postgres. Each developer can set this to a unique value.
- data storage directory - this directory will serve as the root directory for storage of data in the system. During transfers initiated by the daq web service, files will be moved into subdirectories of this system. The subdirectory paths will be constructed from beamline name, experiment name and a path specified by the user in the transfer setup.
- __dm__ system account - This is user __dm__in the Data Management system. This user has administrative priviledge in the Data Management system. This is a user in the 'dm' user table. Each developer can set this to a unique value.
- __dmadmin__ LDAP password - This password provides the Data Management software access to the APS/ANL LDAP system to gather reference to that database. This is a password to an external system and and is therefore a pre-existing password that developers will need to get from the Data Management system administrator.
#### exp-station Node Installation
This node will provide _daq_, _proc_ and _cat_ web services. These services will facilitate transfer of collected data during or after acquisition, processing of the data as necessary, and recording information in the metadata catalog.
To install _dm_ components on the exp-station:
* cd DM\_INSTALL\_DIR/production
* edit etc/dm.deploy.conf to change DM\_CA\_HOST to data-storage
* Edit the file etc/dm.deploy.conf to ensure that the DM\_CA\_HOST is set to the data-storage node.
* ./sbin/install\_dm\_deploy\_data\_station.sh
- This will start the installation process which will prompt for