- Install Ops Manager >
- Configure High Availability >
- Configure a Highly Available Ops Manager Application
Configure a Highly Available Ops Manager Application¶
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Overview¶
The Ops Manager Application provides high availability through use of multiple Ops Manager Application servers behind a load balancer and through use of a replica set to host the Ops Manager Application Database.
Multiple Ops Manager Application Servers¶
The Ops Manager Application’s components are stateless between requests. Any Ops Manager Application server can handle requests as long as all the servers read from the same backing MongoDB instance. If one Ops Manager Application becomes unavailable, another fills requests.
To take advantage of this for high availability, configure a load balancer
to balance between the pool of Ops Manager Application servers. Use the load
balancer of your choice. Configure each application server’s
conf-mms.properties file to point the mms.centralUrl
and mms.backupCentralUrl properties to
the load balancer. For more information, see Ops Manager Configuration Files.
The mms.remoteIp.header property should reflect the HTTP header
set by the load balancer that contains the original client’s IP address,
i.e. X-Forwarded-For. The load balancer then manages the
Ops Manager HTTP Service and Backup HTTP Service
each application server provides.
The Ops Manager Application uses the client’s IP address for auditing, logging, and white listing for the API.
Replica Set for the Backing Instance¶
Deploy a replica set rather than a standalone as the backing MongoDB instance that hosts the Ops Manager Application Database. Replica sets have automatic failover if the primary becomes unavailable.
If the replica set has members in multiple facilities, ensure that a single facility has enough votes to elect a primary if needed. Choose the facility that hosts the core application systems. Place a majority of voting members and all the members that can become primary in this facility. Otherwise, network partitions could prevent the set from being able to form a majority. For details on how replica sets elect primaries, see Replica Set Elections.
You can create backups of the replica set using file system snapshots. File system snapshots use system-level tools to create copies of the device that holds replica set’s data files.
The gen.key File¶
Ops Manager requires an identical gen.key file be stored on each server
hosting an Ops Manager Application or Backup Daemon. The gen.key is a binary file
of 24 random bytes. Ops Manager uses the file to encrypt data at rest in the
databases and to encrypt credentials via the credentials tool.
You can create the gen.key ahead of time and distribute it to each
server, or you can let the Ops Manager Application create the file for you. If you
choose the latter, you must start one Ops Manager Application and copy the generated
gen.key to the other servers before starting the other
Ops Manager Applications. An Ops Manager Application will create a gen.key upon initial
startup if no gen.key exists.
If you choose to create the gen.key ahead of time, before starting any
of the Ops Manager Applications, you can use the OpenSSL rand command. For
example:
The gen.key file is located in /etc/mongodb-mms/ for installations
from a package manager and in ${HOME}/.mongodb-mms/ for installations
from an archive.
Prerequisites¶
Deploy the replica set that hosts the Ops Manager Application Database. To deploy a replica set, see Deploy a Replica Set in the MongoDB manual.
Procedure¶
The following procedure assumes you will let one of the Ops Manager Applications
create the gen.key. If you instead create your own gen.key,
distribute it to the servers before starting any of the Ops Manager Applications.
To configure multiple Ops Manager Applications with load balancing:
Configure a load balancer with the pool of Ops Manager Application servers.¶
This configuration depends on the general configuration of your load balancer and environment.
Update each Ops Manager Application server with the load balanced URL.¶
On each server, edit the conf-mms.properties file to
configure the mms.centralUrl and mms.backupCentralUrl
properties to point to the load balancer URL.
The conf-mms.properties file is located in the
<install_dir>/conf/ directory. See Ops Manager Configuration Files
for more information.
Update each Ops Manager Application server with the replication hosts information.¶
On each server, edit the conf-mms.properties file to
set the mongo.mongoUri property to the connection string of the Ops Manager Application Database. You
must specify at least 3 hosts in the mongo.mongoUri
connection string. For example:
Start one of the Ops Manager Applications.¶
For example, if you installed the Ops Manager Application with an
rpm or deb package, issue the following:
Copy the gen.key file.¶
The gen.key file is located in /etc/mongodb-mms/ for
installations from a package manager and in ${HOME}/.mongodb-mms/
for installations from an archive.
Copy the gen.key file from the running Ops Manager Application’s server to the
appropriate directory on the other Ops Manager Application servers.
Start the remaining Ops Manager Applications.¶
Additional Information¶
For information on making Ops Manager Backup highly available, see Configure a Highly Available Ops Manager Backup Service.