dcrcli

Description

dcrcli is a command line utility to collect following types of diagnostic information for a MongoDB deployment:

• getMongoData output for each node of the cluster
• FTDC data for each node of the cluster
• Logs from all nodes in the cluster

Prerequisites

For a successful collection before running dcrcli, ensure the following conditions are met:

1. Network Access The machine running the dcrcli should have proper access to collect the data from all the nodes in the cluster:
   • Hostnames of all the nodes in the mongo cluster must be resolvable from the machine running dcrcli.
   • Hostnames used are from mongo clusters configuration (e.g. rs.status() output)
   • Allow firewall access from machine running dcrcli to MongoDB instance ports e.g. 27017, 27018 etc
   • When FTDC and mongo logs also needed:
     • Allow firewall ssh access from machine running dcrcli to all mongo nodes in the cluster.
2. MongoDB Shell: Either mongo or mongosh shell must be installed on the machine running dcrcli command.
3. If authentication is enabled in the deployment, the database user must have appropriate permissions (refer to the Minimum Required Permissions section getMongoData README).
   • If the password contains special characters like $ : / ? # [ ] @ then enter them as is percent endoing not needed.
4. Remote Log & FTDC Copy:
   • The machine must have passwordless SSH access to all nodes of the cluster.
   • The passwordless SSH user must have read permissions on the mongo log and FTDC files.
   • The rsync utility must be installed on the machine running dcrcli.
   • if ssh daemon on mongo nodes uses non-default ssh port then use ssh config on the machine running dcrcli to specify the ssh port.
   • if the hostnames used on mongo nodes are not resolvable from machine running dcrcli, add the IP addresses of the mongo nodes to /etc/hosts file on the machine running dcrcli.
5. If data collection is from mongod cluster on v6 and above, the env PATH of the machine running dcrcli should point to mongosh binary.

Usage

Follow these steps to use dcrcli:

1. Download: Obtain the latest release from the releases page.

2. Transfer Binary: Copy the binary to the machine that can access the MongoDB nodes.

3. Set Execute Permissions: Run the following command to give execute permissions to the binary:

   chmod +x <binary-name>

4. Run the binary:

   ./<binary-name>
   

5. Follow the on-screen prompts to start the data collection.

Note: The binary will connect to seed node which can be:

• For a replica set, the seed node can be any node.
• For a sharded cluster, use a mongos instance.

Internal notes

Here are some of the key commands that dcrcli executes:

getMongoData

dcrcli invokes the mongo or mongosh shell with the compatible version of getMongoData.js script. Ensure the mongo or mongosh shell is in the PATH.

rsync

For remote file copy tasks, dcrcli runs the rsync command with the following flags:

rsync -az --include=<file-pattern> --exclude=<file-pattern> --info=progress2 <ssh-username>@<hostname>:<src-path>/ <dest-path>

Note: The utility sequentially connects to each node, which may take time for a deployment with large number of nodes.

Build from Source: To build dcrcli from source, use the following commands based on your operating system:

Linux amd64 build steps example:

1. Assume you are on a Linux amd64 machine
2. Clone the rep

git clone <repo-link>

3. Run the build:

GOOS=linux GOARCH=amd64 go build

License

Apache 2.0

DISCLAIMER

Please note: all tools/ scripts in this repo are released for use "AS IS" without any warranties of any kind, including, but not limited to their installation, use, or performance. We disclaim any and all warranties, either express or implied, including but not limited to any warranty of noninfringement, merchantability, and/ or fitness for a particular purpose. We do not warrant that the technology will meet your requirements, that the operation thereof will be uninterrupted or error-free, or that any errors will be corrected.

Any use of these scripts and tools is at your own risk. There is no guarantee that they have been through thorough testing in a comparable environment and we are not responsible for any damage or data loss incurred with their use.

You are responsible for reviewing and testing any scripts you run thoroughly before use in any non-testing environment.

Thanks,
The MongoDB Support Team