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https://issues.apache.org/jira/browse/YARN-4576?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Junping Du updated YARN-4576:
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Description:
Before YARN-2005, YARN blacklist mechanism is to track the bad nodes by AM: If
AM tried to launch containers on a specific node get failed for several times,
AM will blacklist this node in future resource asking. This mechanism works
fine for normal containers. However, from our observation on behaviors of
several clusters: if this problematic node launch AM failed, then RM could
pickup this problematic node to launch next AM attempts again and again that
cause application failure in case other functional nodes are busy. In normal
case, the customized healthy checker script cannot be so sensitive to mark node
as unhealthy when one or two containers get launched failed.
After YARN-2005, we can have a BlacklistManager in each RMapp, so those nodes
who launching AM attempts failed for specific application before will get
blacklisted. To get rid of potential risks that all nodes being blacklisted by
BlacklistManager, a disable-failure-threshold is involved to stop adding more
nodes into blacklist if hit certain ratio already.
There are already some enhancements for this AM blacklist mechanism: YARN-4284
is to address the more wider case for AM container get launched failure and
YARN-4389 tries to make configuration settings available for change by App to
meet app specific requirement. However, there are still several gaps to address
more scenarios:
1. We may need a global blacklist instead of each app maintain a separated one.
The reason is: AM could get more chance to fail if other AM get failed before.
A quick example is: in a busy cluster, all nodes are busy except two
problematic nodes: node a and node b, app1 already submit and get failed in two
AM attempts on a and b. app2 and other apps should wait for other busy nodes
rather than waste attempts on these two problematic nodes.
2. If AM container failure is recognized as global event instead app own issue,
we should consider the blacklist is not a permanent thing but with a specific
time window.
3. We could have user defined black list polices to address more possible cases
and scenarios, so it reasonable to make blacklist policy pluggable.
4. For some test scenario, we could have whitelist mechanism for AM launching.
5. Some minor issues: it sounds like NM reconnect won't refresh blacklist so
far.
Will try to address all issues here.
was:Current YARN blacklist mechanism is to track the bad nodes by AM: If AM
tried to launch containers on a specific node get failed for several times, AM
will blacklist this node in future resource asking. This mechanism works fine
for normal containers. However, from our observation on behaviors of several
clusters: if this problematic node launch AM failed, then RM could pickup this
problematic node to launch next AM attempts again and again that cause
application failure in case other functional nodes are busy. In normal case,
the customized healthy checker script cannot be so sensitive to mark node as
unhealthy when one or two containers get launched failed. However, in RM side,
we can blacklist these nodes for launching AM for a certain time if launching
AMs get failed before.
> Pluggable blacklist/whitelist policies in launching AM to protect AM failed
> multiple times on problematic nodes
> ---------------------------------------------------------------------------------------------------------------
>
> Key: YARN-4576
> URL: https://issues.apache.org/jira/browse/YARN-4576
> Project: Hadoop YARN
> Issue Type: Improvement
> Components: resourcemanager
> Reporter: Junping Du
> Assignee: Junping Du
> Priority: Critical
>
> Before YARN-2005, YARN blacklist mechanism is to track the bad nodes by AM:
> If AM tried to launch containers on a specific node get failed for several
> times, AM will blacklist this node in future resource asking. This mechanism
> works fine for normal containers. However, from our observation on behaviors
> of several clusters: if this problematic node launch AM failed, then RM could
> pickup this problematic node to launch next AM attempts again and again that
> cause application failure in case other functional nodes are busy. In normal
> case, the customized healthy checker script cannot be so sensitive to mark
> node as unhealthy when one or two containers get launched failed.
> After YARN-2005, we can have a BlacklistManager in each RMapp, so those nodes
> who launching AM attempts failed for specific application before will get
> blacklisted. To get rid of potential risks that all nodes being blacklisted
> by BlacklistManager, a disable-failure-threshold is involved to stop adding
> more nodes into blacklist if hit certain ratio already.
> There are already some enhancements for this AM blacklist mechanism:
> YARN-4284 is to address the more wider case for AM container get launched
> failure and YARN-4389 tries to make configuration settings available for
> change by App to meet app specific requirement. However, there are still
> several gaps to address more scenarios:
> 1. We may need a global blacklist instead of each app maintain a separated
> one. The reason is: AM could get more chance to fail if other AM get failed
> before. A quick example is: in a busy cluster, all nodes are busy except two
> problematic nodes: node a and node b, app1 already submit and get failed in
> two AM attempts on a and b. app2 and other apps should wait for other busy
> nodes rather than waste attempts on these two problematic nodes.
> 2. If AM container failure is recognized as global event instead app own
> issue, we should consider the blacklist is not a permanent thing but with a
> specific time window.
> 3. We could have user defined black list polices to address more possible
> cases and scenarios, so it reasonable to make blacklist policy pluggable.
> 4. For some test scenario, we could have whitelist mechanism for AM launching.
> 5. Some minor issues: it sounds like NM reconnect won't refresh blacklist so
> far.
> Will try to address all issues here.
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