Hbase: Newly added regionserver is not severing requests - hadoop

Question

I'm setting up a Hbase cluster on a cloud infrastructure.
HBase version: 0.94.11
Hadoop version: 1.0.4
Currently I have 4 nodes in my cluster (1 master, 3 regionservers) and I'm using YCSB (yahoo benchmarks) to create a table (500.000 rows) and send READ requests (Asynchronous READ requests).
Everything works fine with this setup (as I'm monitoring the hole process with ganglia and I'm getting lamda, throughput, latency combined with the YCSB's output), but the problem occurs when I add a new regionserver on-the-fly as it doesn't getting any requests.
What "on-the-fly" means:
While the YCSB is sending request to the cluster, I'm adding new regionservers using python scripts.
Addition Process (while the cluster is serving requests):
I'm creating a new VM which will act as the new regionserver and configure every needed aspect (hbase, hadoop, /etc/host, connect to private network, etc)
Stoping **hbase** balancer
Configuring every node in the cluster with the new node's information adding hostname to regioservers filesadding hostname to hadoop's slave fileadding hostname and IP to /etc/host file of every nodeetc
Executing on the master node:
`hadoop/bin/start-dfs.sh`
`hadoop/bin/start-mapred.sh`
`hbase/bin/start-hbase.sh`
(I've also tried to run `hbase start regionserver` on the newly added node and does exactly the same with the last command - starts the regionserver)
Once the newly added node is up and running I'm executing **hadoop** load balancer
When the hadoop load balancer stops I'm starting again the **hbase** load balancer
I'm connecting over ssh to the master node and check that the load balancers (hbase/hadoop) did their job as both the blocks and regions are uniformly spread across all the regionservers/slaves including the new one.
But when I run status 'simple' in the hbase shell I see that the new regionservers are not getting any requests. (below is the output of the command after adding 2 new regionserver "okeanos-nodes-4/5")
hbase(main):008:0> status 'simple'
5 live servers
okeanos-nodes-1:60020 1380865800330
requestsPerSecond=5379, numberOfOnlineRegions=4, usedHeapMB=175, maxHeapMB=3067
okeanos-nodes-2:60020 1380865800738
requestsPerSecond=5674, numberOfOnlineRegions=4, usedHeapMB=161, maxHeapMB=3067
okeanos-nodes-5:60020 1380867725605
requestsPerSecond=0, numberOfOnlineRegions=3, usedHeapMB=27, maxHeapMB=3067
okeanos-nodes-3:60020 1380865800162
requestsPerSecond=3871, numberOfOnlineRegions=5, usedHeapMB=162, maxHeapMB=3067
okeanos-nodes-4:60020 1380866702216
requestsPerSecond=0, numberOfOnlineRegions=3, usedHeapMB=29, maxHeapMB=3067
0 dead servers
Aggregate load: 14924, regions: 19
The fact that they don't serve any requests is also evidenced by the CPU usage, in a serving regionserver is about 70% while in these 2 regioservers is about 2%.
Below is the output of hadoop dfsadmin -report, as you can see the block are evenly distributed (according to hadoop balancer -threshold 2).
root#okeanos-nodes-master:~# /opt/hadoop-1.0.4/bin/hadoop dfsadmin -report
Configured Capacity: 105701683200 (98.44 GB)
Present Capacity: 86440648704 (80.5 GB)
DFS Remaining: 84188446720 (78.41 GB)
DFS Used: 2252201984 (2.1 GB)
DFS Used%: 2.61%
Under replicated blocks: 0
Blocks with corrupt replicas: 0
Missing blocks: 0
-------------------------------------------------
Datanodes available: 5 (5 total, 0 dead)
Name: 10.0.0.11:50010
Decommission Status : Normal
Configured Capacity: 21140336640 (19.69 GB)
DFS Used: 309166080 (294.84 MB)
Non DFS Used: 3851579392 (3.59 GB)
DFS Remaining: 16979591168(15.81 GB)
DFS Used%: 1.46%
DFS Remaining%: 80.32%
Last contact: Fri Oct 04 11:30:31 EEST 2013
Name: 10.0.0.3:50010
Decommission Status : Normal
Configured Capacity: 21140336640 (19.69 GB)
DFS Used: 531652608 (507.02 MB)
Non DFS Used: 3852300288 (3.59 GB)
DFS Remaining: 16756383744(15.61 GB)
DFS Used%: 2.51%
DFS Remaining%: 79.26%
Last contact: Fri Oct 04 11:30:32 EEST 2013
Name: 10.0.0.5:50010
Decommission Status : Normal
Configured Capacity: 21140336640 (19.69 GB)
DFS Used: 502910976 (479.61 MB)
Non DFS Used: 3853029376 (3.59 GB)
DFS Remaining: 16784396288(15.63 GB)
DFS Used%: 2.38%
DFS Remaining%: 79.4%
Last contact: Fri Oct 04 11:30:32 EEST 2013
Name: 10.0.0.4:50010
Decommission Status : Normal
Configured Capacity: 21140336640 (19.69 GB)
DFS Used: 421974016 (402.43 MB)
Non DFS Used: 3852365824 (3.59 GB)
DFS Remaining: 16865996800(15.71 GB)
DFS Used%: 2%
DFS Remaining%: 79.78%
Last contact: Fri Oct 04 11:30:29 EEST 2013
Name: 10.0.0.10:50010
Decommission Status : Normal
Configured Capacity: 21140336640 (19.69 GB)
DFS Used: 486498304 (463.96 MB)
Non DFS Used: 3851759616 (3.59 GB)
DFS Remaining: 16802078720(15.65 GB)
DFS Used%: 2.3%
DFS Remaining%: 79.48%
Last contact: Fri Oct 04 11:30:29 EEST 2013
I've tried stopping YCSB, restarting hbase master and restarting YCSB but with no lack.. these 2 nodes don't serve any requests!
As there are many log and conf files, I have created a zip file with logs and confs (both hbase and hadoop) of the master, a healthy regionserver serving requests and a regionserver not serving requests.
https://dl.dropboxusercontent.com/u/13480502/hbase_hadoop_logs__conf.zip
Thank you in advance!!

Answer 1

I found what was going on and it had nothing to do with Hbase... I have forgotten to add the hostname and IP of the new RS to the YCSB server VM (/etc/hosts file).... :-(