mongodump: Usage, Options & Common CI Errors
mongodump writes a binary BSON backup of MongoDB data.
mongodump produces the BSON dumps mongorestore reloads in CI. Like mongosh, its failures cluster around the connection URI and authSource, plus the archive-vs-directory output choice.
What it does
mongodump connects to a MongoDB server and writes BSON files (plus metadata) for a database or collection into a dump directory, or into a single --archive file. It is the standard logical backup tool, paired with mongorestore.
Common usage
mongodump --uri="mongodb://localhost:27017/app" --out=dump
mongodump --uri="mongodb://user:pass@localhost:27017/app?authSource=admin" --gzip --out=dump
mongodump --host 127.0.0.1 --port 27017 --db app --collection users --out=dump
mongodump --uri="mongodb://localhost:27017/app" --archive=app.archive --gzipOptions
| Flag | What it does |
|---|---|
| --uri="..." | Connection string |
| --db / --collection | Limit to one database / collection |
| --out <dir> | Write BSON files into a directory |
| --archive[=file] | Write a single archive (file or stdout) |
| --gzip | Compress the output |
| --query '{...}' | Dump only matching documents |
Common errors in CI
Failed: ... Authentication failed. - supply the right credentials and authSource in the URI (admin users need ?authSource=admin). "could not connect to server ... connection() : dial tcp 127.0.0.1:27017: connect: connection refused" means the server is not up; wait on mongosh ping first. If you write --archive (one file), mongorestore must read with --archive too; a directory dump restores from the directory.