YARN-8389. Improve the description of machine-list property in Federation docs. Contributed by Takanobu Asanuma.

(cherry picked from commit 61fc7f73f21b0949e27ef3893efda757d91a03f9)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/Federation.md

@@ -218,7 +218,7 @@ SQL-Server scripts are located in **sbin/FederationStateStore/SQLServer/**.
 |`yarn.federation.policy-manager` | `org.apache.hadoop.yarn.server.federation.policies.manager.WeightedLocalityPolicyManager` | The choice of policy manager determines how Applications and ResourceRequests are routed through the system. |
 |`yarn.federation.policy-manager-params` | `<binary>` | The payload that configures the policy. In our example a set of weights for router and amrmproxy policies. This is typically generated by serializing a policymanager that has been configured programmatically, or by populating the state-store with the .json serialized form of it. |
 |`yarn.federation.subcluster-resolver.class` | `org.apache.hadoop.yarn.server.federation.resolver.DefaultSubClusterResolverImpl` | The class used to resolve which subcluster a node belongs to, and which subcluster(s) a rack belongs to. |
-| `yarn.federation.machine-list` | `node1,subcluster1,rack1\n node2 , subcluster2, RACK1\n node3,subcluster3, rack2\n node4, subcluster3, rack2\n` | a list of Nodes, Sub-clusters, Rack, used by the `DefaultSubClusterResolverImpl` |
+|`yarn.federation.machine-list` | `<path of macihne-list file>` | Path of machine-list file used by `SubClusterResolver`. Each line of the file is a node with sub-cluster and rack information. Below is the example: <br/> <br/> node1, subcluster1, rack1 <br/> node2, subcluster2, rack1 <br/> node3, subcluster3, rack2 <br/> node4, subcluster3, rack2 |
 
 ###ON RMs:
 
@@ -226,8 +226,7 @@ These are extra configurations that should appear in the **conf/yarn-site.xml**
 
 | Property | Example | Description |
 |:---- |:---- |
-|`yarn.resourcemanager.epoch` | `<unique-epoch>` | The seed value for the epoch. This is used to guarantee uniqueness of container-IDs generate by different RMs. It must therefore be unique among sub-clusters and `well-spaced` to allow for failures which increment epoch. Increments of 1000 allow for a large number of sub-clusters and
- practically ensure near-zero chance of collisions (a clash will only happen if a container is still alive for 1000 restarts of one RM, while the next RM never restarted, and an app requests more containers). |
+|`yarn.resourcemanager.epoch` | `<unique-epoch>` | The seed value for the epoch. This is used to guarantee uniqueness of container-IDs generate by different RMs. It must therefore be unique among sub-clusters and `well-spaced` to allow for failures which increment epoch. Increments of 1000 allow for a large number of sub-clusters and practically ensure near-zero chance of collisions (a clash will only happen if a container is still alive for 1000 restarts of one RM, while the next RM never restarted, and an app requests more containers). |
 
 Optional:
 
@@ -285,7 +284,7 @@ In order to submit jobs to a Federation cluster one must create a seperate set o
 | Property | Example | Description |
 |:--- |:--- |
 | `yarn.resourcemanager.address` | `<router_host>:8050` | Redirects jobs launched at the client to the router's client RM port. |
-| `yarn.resourcemanger.scheduler.address` | `localhost:8049` | Redirects jobs to the federation AMRMProxy port.|
+| `yarn.resourcemanager.scheduler.address` | `localhost:8049` | Redirects jobs to the federation AMRMProxy port.|
 
 Any YARN jobs for the cluster can be submitted from the client configurations described above. In order to launch a job through federation, first start up all the clusters involved in the federation as described [here](../../hadoop-project-dist/hadoop-common/ClusterSetup.html). Next, start up the router on the router machine with the following command: