A few assumptions:

There is a special configuration type for this case which simplifies setting needed to run Tigase as an external component:

'config-type' = 'component'

Knowing that we can now create simple configuration file for Tigase XMPP Server:

admins = [ 'admin@devel.tigase.org' ]
'config-type' = 'component'
debug = [ 'server' ]
'virtual-hosts' = [ 'devel.tigase.org' ]
dataSource {
    default () {
        uri = 'master_server_default_database_url'
    }
}
userRepository {
    default () {}
}
authRepository {
    default () {}
}
muc (class: tigase.muc.MUCComponent) {}
ext () {
}

where master_server_default_database_url is the same URL as the one used on the main server for default data source.

With that in place we can use ad-hoc commands or Admin UI on the main server to configure Tigase XMPP Server to accept external component connections and to connect from the external component to the master server.

Adding external component connection settings to the manager (ext-man) using Admin UI. 

You need to pass:

Additional options may be left with defaults.

Suppose you want to run more than one component as an external components within one Tigase instance. Let’s add another - PubSub component to the configuration above and see how to set it up.

The most straightforward way is just to add another component to the server running in the component mode for the component domain

admins = [ 'admin@devel.tigase.org' ]
'config-type' = 'component'
debug = [ 'server' ]
'virtual-hosts' = [ 'devel.tigase.org' ]
dataSource {
    default () {
        uri = 'jdbc:derby:/tigasedb'
    }
}
userRepository {
    default () {}
}
authRepository {
    default () {}
}
muc (class: tigase.muc.MUCComponent) {}
pubsub (class: tigase.pubsub.PubSubComponent) {}
ext () {}

and then to add new connection domain to the main server external component settings and to the external component manager settings. You basically do the same thing as you did while adding only MUC component as the external component.

Please note however that we are opening two connections to the same server. This can waste resources and over-complicate the system. For example, what if we want to run even more components? Opening a separate connection for each component is a tad overkill.

In fact there is a way to reuse the same connection for all component domains running as an external component. The property bind-ext-hostnames contains a comma separated list of all hostnames (external domains) which should reuse the existing connection.

There is one catch however. Since you are reusing connections (hostname binding is defined in XEP-0225 only), you must use this protocol for the functionality.

Here is an example configuration with a single connection over the XEP-0225 protocol used by both external domains:

admins = [ 'admin@devel.tigase.org' ]
'bind-ext-hostnames' = [ 'pubsub.devel.tigase.org' ]
'config-type' = 'component'
debug = [ 'server' ]
'virtual-hosts' = [ 'devel.tigase.org' ]
dataSource {
    default () {
        uri = 'jdbc:derby:/tigasedb'
    }
}
ext () {
}
userRepository {
    default () {}
}
authRepository {
    default () {}
}
muc (class: tigase.muc.MUCComponent) {}
pubsub (class: tigase.pubsub.PubSubComponent) {}

With this configuration you do not need to configure entries in ext-man for PubSub component, only for MUC component but you need to user client as the value for protocol field.

A few assumptions:

There is a special configuration type for this case which simplifies setting needed to run Tigase as an external component:

'config-type' = 'component'

This generates a configuration for Tigase with only one component loaded by default - the component used for external component connection. If you use this configuration type, your config.tdsl file may look like this:

admins = [ 'admin@devel.tigase.org' ]
'config-type' = 'component'
debug = [ 'server' ]
'virtual-hosts' = [ 'devel.tigase.org' ]
dataSource {
    default () {
        uri = 'jdbc:derby:/tigasedb'
    }
}
userRepository {
    default () {}
}
authRepository {
    default () {}
}
muc (class: tigase.muc.MUCComponent) {}
ext () {
}

To make this new instance connect to the Tigase XMPP Server, you need to create one more file with external connection configuration at etc/externalComponentItems which will be loaded to the local database and then removed.

muc.devel.tigase.org:muc-pass:connect:5270:devel.tigase.org:accept

Suppose you want to run more than one component as an external components within one Tigase instance. Let’s add another - PubSub component to the configuration above and see how to set it up.

The most straightforward way is just to add another external component connection to the main server for the component domain using Admin UI or ad-hoc command on the main server.

Then we can use following configuration on the server running in the component mode:

admins = [ 'admin@devel.tigase.org' ]
'config-type' = 'component'
debug = [ 'server' ]
'virtual-hosts' = [ 'devel.tigase.org' ]
dataSource {
    default () {
        uri = 'jdbc:derby:/tigasedb'
    }
}
userRepository {
    default () {}
}
authRepository {
    default () {}
}
muc (class: tigase.muc.MUCComponent) {}
pubsub (class: tigase.pubsub.PubSubComponent) {}
ext () {
}

and we need to create a file with configuration for external component connection which will be loaded to the internal database:

muc.devel.tigase.org:muc-pass:connect:5270:devel.tigase.org:accept
pubsub.devel.tigase.org:pubsub-pass:connect:5270:devel.tigase.org:accept

Please note however that we are opening two connections to the same server. This can waste resources and over-complicate the system. For example, what if we want to run even more components? Opening a separate connection for each component is a tad overkill.

In fact there is a way to reuse the same connection for all component domains running as an external component. The property bind-ext-hostnames contains a comma separated list of all hostnames (external domains) which should reuse the existing connection.

There is one catch however. Since you are reusing connections (hostname binding is defined in XEP-0225 only), you must use this protocol for the functionality.

Here is an example configuration with a single connection over the XEP-0225 protocol used by both external domains:

admins = [ 'admin@devel.tigase.org' ]
'bind-ext-hostnames' = [ 'pubsub.devel.tigase.org' ]
'config-type' = 'component'
debug = [ 'server' ]
'virtual-hosts' = [ 'devel.tigase.org' ]
dataSource {
    default () {
        uri = 'jdbc:derby:/tigasedb'
    }
}
ext () {
}
userRepository {
    default () {}
}
authRepository {
    default () {}
}
muc (class: tigase.muc.MUCComponent) {}
pubsub (class: tigase.pubsub.PubSubComponent) {}

and example of the external connections configuration file:

muc.devel.tigase.org:muc-pass:connect:5270:devel.tigase.org:client