Configure the Migrator

Use this section to choose how to provide configuration settings to the migrator. The following are the different configuration methods in the order of precedence for Instance Migrator:

1. Environmental Variables

2. Application Properties

3. Interactive Shell

Note

When configuration export uses encrypted secrets, you must provide the cipher password. Refer to Cipher Password Configuration for more details.

Key Configuration Options

The following block displays the key configuration fields that may be necessary for Instance Migrator.

# Application mode
mode=CONFIGURATION_READ|CONFIGURATION_WRITE|CONTENT_MIGRATION|CONTENT_POLLING|ALL

# Source Nexus instance
source-nexus-url=http://localhost:8081
source-nexus-username=admin
source-nexus-password=admin123

# Target cloud Nexus instance
target-nexus-url=https://my-org.repository.sonatype.com
target-nexus-username=myuser
target-nexus-password=mypass

# Target self hosted Nexus instance
target-nexus-url=http://localhost:8082
target-nexus-username=admin
target-nexus-password=admin123

# Configuration storage
configuration-json=migration-config.json
state-directory=state

# HTTP timeouts (milliseconds)
connection-timeout-ms=10000
read-timeout-ms=30000

# Repository filtering (optional)
override-repositories=repo1,repo2,repo3

Environment Variables

Use environment variables when you want to preload settings before starting the migrator or avoid entering values interactively each time. Command-line arguments may be provided as environment variables using uppercase with underscores.

Below is an example configuration for self-hosted (OrientDB) to self-hosted (PostgreSQL) migration:

export SOURCE_NEXUS_URL=http://localhost:8081
export SOURCE_NEXUS_USERNAME=admin
export SOURCE_NEXUS_PASSWORD=admin123
export TARGET_NEXUS_URL=http://localhost:8082
export TARGET_NEXUS_USERNAME=admin
export TARGET_NEXUS_PASSWORD=admin123
export CONFIGURATION_JSON=my-config.json
export ASSET_QUERY_THREADS=8
export ASSET_MIGRATION_THREADS=16

Application Properties

Configuration may also be provided via application.properties. This is useful when you want a file-based configuration that can be reused across runs.

The following is an example configuration for self-hosted (OrientDB) to self-hosted (PostgreSQL) migration:

source-nexus-url=http://localhost:8081
source-nexus-username=admin
source-nexus-password=admin123
target-nexus-url=http://localhost:8082
target-nexus-username=admin
target-nexus-password=admin123
target-cipher-password=<strong-password-minimum-24-chars>
state-directory=migration-state
configuration-json=nexus-config.json
connection-timeout-ms=10000
read-timeout-ms=600000
asset-query-read-timeout-ms=10000
asset-query-max-retries=5
polling-interval-seconds=60
asset-query-threads=2
asset-migration-threads=16
asset-migration-polling-threads=2
transfer-complete-notification-enabled=true
transfer-complete-notification-interval-hours=24

Interactive Shell

Use interactive shell configuration when you want to set or change values manually while working in the shell. You can set the configuration settings using config set command.

Below is an example configuration for self-hosted Nexus Repository to a cloud instance:

config set source-nexus-url http://localhost:8081
config set source-nexus-username admin
config set source-nexus-password admin123
config set target-nexus-url https://my-org.repository.sonatype.com
config set target-nexus-username myuser
config set target-nexus-password mypass

Cipher Password Configuration

Instance Migrator supports automatic encryption of sensitive configuration values during migration. When encrypted secrets like SMTP passwords, LDAP bind passwords and database credentials are detected in the configuration export, you must provide the cipher password that was used on the source Nexus instance. This password is transmitted to the target instance to enable it to decrypt the encrypted secrets.

Important

The migration fails with a clear error message when encrypted secrets are present and the cipher password is missing.

Password Requirements:

• The password should be at least 24 characters
• Use cryptographically random passwords (recommended)
• Generate the password through openssl rand -base64 32

Configuration Options:

• Environment Variable (Recommended for Security):

export TARGET_CIPHER_PASSWORD=$(openssl rand -base64 32)

• Application Properties:

# Generate strong password: openssl rand -base64 32
target-cipher-password=<strong-password-minimum-24-chars>

• Interactive Shell:

config set target-cipher-password $(openssl rand -base64 32)

Performance And Concurrency Settings

Instance Migrator uses configurable thread pools for parallel processing. It supports configurable concurrency, batch-based asset querying, thread-safe shared state, and graceful shutdown.

• Configurable Concurrency

Set max-threads to control parallel operations (default: 10)

• Batch Processing

Assets are queried in batches. It is configurable via batch-size (default: 100)

The migrator provides three independent thread pool configurations for optimal performance. These settings help you balance migration speed against CPU, memory, network usage, and source-instance stability. In general, higher values can improve throughput, but they can also increase system load. Lower values reduce load, but may increase total migration time.

You can also adjust timeout settings using connection-timeout-ms and read-timeout-ms to support slower environments or large migrations.

For conservative operation, especially when the source OrientDB instance is under memory pressure, use lower thread counts.

config set asset-query-threads 1
config set asset-migration-threads 4
config set read-timeout-ms 1200000
config set connection-timeout-ms 20000