Author: elserj
Date: Sun Jan 10 19:22:13 2016
New Revision: 1723954
URL: http://svn.apache.org/viewvc?rev=1723954&view=rev
Log:
More grammar/nit-picky fixes to the placement doc.
Modified:
incubator/slider/site/trunk/content/docs/placement.md
Modified: incubator/slider/site/trunk/content/docs/placement.md
URL:
http://svn.apache.org/viewvc/incubator/slider/site/trunk/content/docs/placement.md?rev=1723954&r1=1723953&r2=1723954&view=diff
==============================================================================
--- incubator/slider/site/trunk/content/docs/placement.md (original)
+++ incubator/slider/site/trunk/content/docs/placement.md Sun Jan 10 19:22:13
2016
@@ -38,7 +38,7 @@ the cluster. For details on the implemen
A Slider Application Instance consists of the Application Master âSlider's
codeâ and
the components requested in the `resources.json` file. For each component,
-Slider requests a new YARN Container, which is then allocated in the Hadoo
cluster
+Slider requests a new YARN Container, which is then allocated in the Hadoop
cluster
by YARN. The Slider application starts the component within the container,
and monitors its lifecycle.
@@ -59,7 +59,7 @@ there is no capacity on nodes with the l
âeven if there is space elsewhere.
1. **Named Nodes/Racks**. Slider lists the explicit hosts and racks upon which
-a component can be allocated. If there is no capacity in these nodes locations,
+a component can be allocated. If there is no capacity in these locations,
the request will be unsatisfied âeven if there is space elsewhere.
1. **Named Nodes/Racks with relaxation**. Slider lists the explicit hosts and
@@ -99,7 +99,7 @@ placement ensures that there is no confl
prevent any conflict across component types, or between Slider/YARN
applications.
-Anothe need is history-based placement: re-instantiating component instances on
+Another need is history-based placement: re-instantiating component instances
on
the machine(s) on which they last ran.
This can deliver performance and startup advantages, or, for
some applications, essential to recover data persisted on the server.
@@ -127,12 +127,12 @@ which instances were created, rather tha
Servers were previously running on Node 17". On restart Slider can simply
request
one instance of a Region Server on a specific node, leaving the other instance
to be arbitrarily deployed by YARN. This strategy should help reduce the
affinity
-in the component deployment, so increase their resilience to failure.
+in the component deployment, increasing their resilience to failure.
1. There is no need to make sophisticated choices on which nodes to request
re-assignment âsuch as recording the amount of data persisted by a previous
instance and prioritizing nodes based on such data. More succinctly 'the
-only priority needed when asking for nodes is *ask for the most recently used*.
+only priority needed when asking for nodes is *ask for the most recently
used*'.
1. If a component instance fails on a specific node, asking for a new
container on
that same node is a valid first attempt at a recovery strategy.
@@ -144,9 +144,10 @@ that same node is a valid first attempt
The policy for placing a component can be set in the resources.json file,
via the `yarn.component.placement.policy` field.
-Here are the currently supported placement policies, with their
+Here are the currently supported placement policies
Note that
+
1. These are orthogonal to labels: when "anywhere" is used, it means
"anywhere that the label expression permits".
1. The numbers are (currently) part of a bit-mask. Other combinations may
@@ -185,7 +186,7 @@ failed, then the request will never be s
New instances (i.e. ones for which there is no historical placement)
will be requested anywhere.
-Note: As of Jan 2016 tThere is no anti-affinity placement when expanding
+Note: As of Jan 2016, there is no anti-affinity placement when expanding
strict placements
[SLIDER-980](https://issues.apache.org/jira/browse/SLIDER-980).
It's possible to work around this by requesting the initial set of instances
using anti-affinity, then editing resources.json to switch to strict placements
