Community Articles
Find and share helpful community-sourced technical articles
Announcements
Alert: Welcome to the Unified Cloudera Community. Former HCC members be sure to read and learn how to activate your account here.
Labels (1)

Whether you're creating an Ambari cluster from scratch, taking over an existing cluster, or growing your cluster over time, it is imperative to tune Ambari and MySQL to work at a large scale of 1000-3000 Ambari Agents.

Ambari Server Configs

First, increase the memory used by Ambari. For large clusters, 8 GB of memory should be sufficient. If you have more than 10 concurrent users, increase it to 16 GB.

Edit /var/lib/ambari-server/ambari-env.sh and change the -Xmn setting.

export AMBARI_JVM_ARGS=$AMBARI_JVM_ARGS' -Xms2048m -Xmx8192m

Edit /etc/ambari-server/conf/ambari.properties with the following configs

# The size of the Jetty connection pool used for handling incoming Ambari Agent requests.
# 10 hosts => 25
# 50 hosts => 35
# 100 hosts => 75
# 500 hosts => 100	
agent.threadpool.size.max=100
# Determines whether current alerts should be cached.
# Enabling this can increase performance on large cluster, but can also result in lost alert data
# if the cache is not flushed frequently.
alerts.cache.enabled=true
# The size of the alert cache.
# Less than 50 hosts => 50000
# More than 50 hosts => 100000
alerts.cache.size=100000
# The number of threads used to handle alerts received from the Ambari Agents.
# The value should be increased as the size of the cluster increases.
# Less than 50 hosts => 2
# More than 50 hosts => 4
alerts.execution.scheduler.maxThreads=4

After performing these changes, restart Ambari Server.

Move an existing Ambari DB from a spinning disk to a SSD

It is highly suggested to use a Solid State Drive for the Ambari Database since this will be much faster.

Check the throughput of the disk in which Ambari’s database (Postgres, MySQL, MariaDB, or Oracle) is on.Ideally, it should be a Solid State Drive or support at least 200 IOPS and be either on the same host as Ambari or only a 1-2 hops away.

Type Details IOPS Throughput
HDD 10,000 rpm SAS drive 175-210 100 MB/s
SSD solid-state 500+ 500+ MB/s

1. ambari-server stop

2. Take a backup of the Ambari database,

		mysqldump -u root ambari > /tmp/ambari.sql

3. Stop MySQL server, copy its data, and change the directory.

service mysqld stop
cp -R -p /var/lib/mysql /mnt/disks/ssd/mysql
cat /etc/my.cnf
sed -ie 's/\/var\/lib\/mysql/\/mnt\/disks\/ssd\/mysql/g' /etc/my.cnf

4. Create symlink for sock file and start MySQL

ln -s /mnt/disks/ssd/mysql/mysql.sock /var/lib/mysql/mysql.sock
service mysqldstart

5. Ensure Ambari DB is accessible.

mysql -u root -p
show databases;
use ambari;
show tables;
select count(*) from hosts;

MySQL Optimizations

First and foremost, if you're on an older version of MySQL, you can try to update it to MySQL 5.6 or 5.7, which has a lot of performance improvements.

Connect to the MySQL DB and inspect these variables. E.g.,

SHOW VARIABLES LIKE 'name';These suggested values assume that only Ambari Database’s is on the MySQL Server.If you have other databases in the same MySQL Server, increment by these values.

WARNING: Never stop MySQL server while Ambari Server is running.

Variable Suggested Value

innodb_log_buffer_size

512M
innodb_buffer_pool_size 16G
innodb_file_io_threads (deprecated in MySQL 5.5) 16
innodb_log_file_size 5M
innodb_thread_concurrency 32
join_buffer_size 512M
key_buffer_size 16G
max_connections 500
max_allowed_packet 1024M
max_heap_table_size 64M
query_cache_limit 16M
query_cache_size 512M
read_rnd_buffer_size 128M
sort_buffer_size 128M
table_open_cache 1024
thread_cache_size 128
thread_stack 256K

To change these values.1. Stop MySQL: service mysqld stop

2. Edit the configs in /etc/my.cnf , under the “[mysqld]” section (note, it may be in a different location).

3. Start MySQL: service mysqld start

1,516 Views
Don't have an account?
Coming from Hortonworks? Activate your account here
Version history
Revision #:
1 of 1
Last update:
‎01-31-2017 01:47 AM
Updated by:
 
Contributors
Top Kudoed Authors