Keith Turner created ACCUMULO-2036:
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Summary: Mappers are not running locally
Key: ACCUMULO-2036
URL: https://issues.apache.org/jira/browse/ACCUMULO-2036
Project: Accumulo
Issue Type: Bug
Reporter: Keith Turner
Fix For: 1.6.0
I ran listscans in the Accumulo shell while running continuous verify on small
cluster and almost not map task were running locally.
I think ACCUMULO-1585 has broken mapper locality in 1.6.0-SNAPSHOT. Before
that change Accumulo would always store IP addrs. Code like the following in
o.a.a.c.client.mapreduce.AbstractInputFormat.getSplits() would translate IPs to
hostnames.
{code:java}
if (location == null) {
InetAddress inetAddress = InetAddress.getByName(ip);
location = inetAddress.getHostName();
hostNameCache.put(ip, location);
}
{code}
In my case I configured Accumulo to use hostnames, but not fully qualified
ones. So I think the above code was just passing the non-quallified hostname
through. I suspected that maybe hadoop wanted FQDN and changed the code the
following and mappers ran locally. I need to confirm what hadoop is expecting.
I think the above code will result in a FQDN if given an IP, but not a
non-quallified hostname. So this is not an issue for 1.4 or 1.5.
{code:java}
if (location == null) {
InetAddress inetAddress = InetAddress.getByName(ip);
location = inetAddress.getCanonicalHostName();
hostNameCache.put(ip, location);
}
{code}
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