[id='jgroups_system_props-{context}']
= System Properties for Default JGroups Stacks
Use system properties with default JGroups stacks.

.Common Properties

The following system properties apply to all JGroups stacks, including
`default-jgroups-udp.xml` and `default-jgroups-tcp.xml`:

[%header,cols="1,3,2,1"]
|===

| System Property
| Description
| Default Value
| Required/Optional

| `jgroups.bind.address`
| Bind address for cluster transport.
| `SITE_LOCAL`
| Optional

| `jgroups.bind.port`
| Bind port for the socket.
| `7800`
| Optional

| `jgroups.mcast_addr`
| IP address for multicast, both discovery and inter-cluster communication. The IP address must be a valid "class D" address that is suitable for IP multicast.
| `228.6.7.8`
| Optional

| `jgroups.mcast_port`
| Port for the multicast socket.
| `46655`
| Optional

| `jgroups.ip_ttl`
| Time-to-live (TTL) for IP multicast packets. The value defines the number of network hops a packet can make before it is dropped.
| 2
| Optional

| `jgroups.thread_pool.min_threads`
| Minimum number of threads for the thread pool.
| 0
| Optional

| `jgroups.thread_pool.max_threads`
| Maximum number of threads for the thread pool.
| 200
| Optional

| `jgroups.join_timeout`
| Maximum number of milliseconds to wait for join requests to succeed.
| 2000
| Optional

|===


.Amazon EC3

The following system properties apply to `default-jgroups-ec2.xml`:

[%header,cols="1,3,2,1"]
|===

| System Property
| Description
| Default Value
| Required/Optional

| `jgroups.s3.access_key`
| Amazon S3 access key for an S3 bucket.
| No default value.
| Optional

| `jgroups.s3.secret_access_key`
| Amazon S3 secret key used for an S3 bucket.
| No default value.
| Optional

| `jgroups.s3.bucket`
| Name of the Amazon S3 bucket. The name must exist and be unique.
| No default value.
| Optional

|===

.Kubernetes

The following system properties apply to `default-jgroups-kubernetes.xml`:

[%header,cols="1,3,2,1"]
|===

| System Property
| Description
| Default Value
| Required/Optional

| `jgroups.dns.query`
| Sets the DNS record that returns cluster members.
| N/A
| Required if you do not set the `dns_query` parameter.

|===

.Google Cloud Platform

The following system properties apply to `default-jgroups-google.xml`:

[%header,cols="1,3,2,1"]
|===

| System Property
| Description
| Default Value
| Required/Optional

| `jgroups.google.bucket_name`
| Name of the Google Compute Engine bucket. The name must exist and be unique.
| N/A
| Required if you do not set the `dns_query` parameter.

|===

.Reference

* link:http://www.jgroups.org/manual4/index.html#SystemProperties[JGroups System Properties]
* link:http://jgroups.org/manual/html/protlist.html[JGroups Protocol List]
