NEO4J Availability

High availability to neo4j: Clients → HAproxy → neo4j servers

/etc/security/limits.conf

neo4j   soft    nofile  40000
neo4j   hard    nofile  40000

echo 'deadline' > /sys/block/sda/queue/scheduler
cat               /sys/block/sda/queue/scheduler
noop [deadline] cfq

/.../neo4j/conf/neo4j-server.properties

################################################################
# Neo4j
#
# neo4j-server.properties - runtime operational settings
#
################################################################

#***************************************************************
# Server configuration
#***************************************************************

# location of the database directory
org.neo4j.server.database.location=data/graph.db

# Low-level graph engine tuning file
org.neo4j.server.db.tuning.properties=conf/neo4j.properties

# Database mode
# Allowed values:
# HA - High Availability
# SINGLE - Single mode, default.
# To run in High Availability mode, configure the neo4j.properties config file, then uncomment this line:
org.neo4j.server.database.mode=HA

# Let the webserver only listen on the specified IP. Default is localhost (only
# accept local connections). Uncomment to allow any connection. Please see the
# security section in the neo4j manual before modifying this.
org.neo4j.server.webserver.address=0.0.0.0

# Require (or disable the requirement of) auth to access Neo4j
dbms.security.auth_enabled=true

#
# HTTP Connector
#

# http port (for all data, administrative, and UI access)
org.neo4j.server.webserver.port=7474

#
# HTTPS Connector
#

# Turn https-support on/off
org.neo4j.server.webserver.https.enabled=true

# https port (for all data, administrative, and UI access)
org.neo4j.server.webserver.https.port=7473

# Certificate location (auto generated if the file does not exist)
dbms.security.tls_certificate_file=conf/ssl/snakeoil.cert

# Private key location (auto generated if the file does not exist)
dbms.security.tls_key_file=conf/ssl/snakeoil.key

# Internally generated keystore (don't try to put your own
# keystore there, it will get deleted when the server starts)
org.neo4j.server.webserver.https.keystore.location=data/keystore

# Comma separated list of JAX-RS packages containing JAX-RS resources, one
# package name for each mountpoint. The listed package names will be loaded
# under the mountpoints specified. Uncomment this line to mount the
# org.neo4j.examples.server.unmanaged.HelloWorldResource.java from
# neo4j-server-examples under /examples/unmanaged, resulting in a final URL of
# http://localhost:7474/examples/unmanaged/helloworld/{nodeId}
#org.neo4j.server.thirdparty_jaxrs_classes=org.neo4j.examples.server.unmanaged=/examples/unmanaged


#*****************************************************************
# HTTP logging configuration
#*****************************************************************

# HTTP logging is disabled. HTTP logging can be enabled by setting this
# property to 'true'.
org.neo4j.server.http.log.enabled=false

# Logging policy file that governs how HTTP log output is presented and
# archived. Note: changing the rollover and retention policy is sensible, but
# changing the output format is less so, since it is configured to use the
# ubiquitous common log format
org.neo4j.server.http.log.config=conf/neo4j-http-logging.xml

#*****************************************************************
# Administration client configuration
#*****************************************************************

# location of the servers round-robin database directory. possible values:
# - absolute path like /var/rrd
# - path relative to the server working directory like data/rrd
# - commented out, will default to the database data directory.
org.neo4j.server.webadmin.rrdb.location=data/rrd


#*****************************************************************
# Neo4j Browser configuration
#*****************************************************************

# Whitelist of hosts for the Neo4j Browser to be allowed to fetch content from.
# Set to '*' to allow all hosts.
dbms.browser.remote_content_hostname_whitelist=http://guides.neo4j.com,https://guides.neo4j.com,http://localhost,https://localhost

# Allow outgoing connections from Neo4j Browser.
dbms.security.allow_outgoing_browser_connections=true

/.../neo4j/conf/neo4j.properties

################################################################
# Neo4j
#
# neo4j.properties - database tuning parameters
#
################################################################

# Enable this to be able to upgrade a store from an older version.
#allow_store_upgrade=true

# The amount of memory to use for mapping the store files, in bytes (or
# kilobytes with the 'k' suffix, megabytes with 'm' and gigabytes with 'g').
# If Neo4j is running on a dedicated server, then it is generally recommended
# to leave about 2-4 gigabytes for the operating system, give the JVM enough
# heap to hold all your transaction state and query context, and then leave the
# rest for the page cache.
# The default page cache memory assumes the machine is dedicated to running
# Neo4j, and is heuristically set to 50% of RAM minus the max Java heap size.
#dbms.pagecache.memory=10g
dbms.security.auth_enabled=false
# Enable this to specify a parser other than the default one.
#cypher_parser_version=2.0

# Set the root directory for use with file URLs (`file:///`) in LOAD CSV.
# If enabled, file URLs will refer to locations inside the `data/import`
# directory. I.e. `file:///movies/actors.csv` will load from the file
# `data/import/movies/actors.csv`.
#dbms.security.load_csv_file_url_root=data/import

# Keep logical logs, helps debugging but uses more disk space, enabled for
# legacy reasons To limit space needed to store historical logs use values such
# as: "7 days" or "100M size" instead of "true".
#keep_logical_logs=7 days

# Enable shell server so that remote clients can connect via Neo4j shell.
#remote_shell_enabled=true
# The network interface IP the shell will listen on (use 0.0.0.0 for all interfaces).
#remote_shell_host=127.0.0.1
# The port the shell will listen on, default is 1337.
#remote_shell_port=1337

# Enable online backups to be taken from this database.
online_backup_enabled=true

# Port to listen to for incoming backup requests.
online_backup_server=192.168.168.33:6362


# Uncomment and specify these lines for running Neo4j in High Availability mode.
# See the High availability setup tutorial for more details on these settings
# http://neo4j.com/docs/2.3.2/ha-setup-tutorial.html

# ha.server_id is the number of each instance in the HA cluster. It should be
# an integer (e.g. 1), and should be unique for each cluster instance.
ha.server_id=1

# ha.initial_hosts is a comma-separated list (without spaces) of the host:port
# where the ha.cluster_server of all instances will be listening. Typically
# this will be the same for all cluster instances.
ha.initial_hosts=192.168.168.33:5001,192.168.168.34:5001

# IP and port for this instance to listen on, for communicating cluster status
# information iwth other instances (also see ha.initial_hosts). The IP
# must be the configured IP address for one of the local interfaces.
ha.cluster_server=192.168.168.33:5001

# IP and port for this instance to listen on, for communicating transaction
# data with other instances (also see ha.initial_hosts). The IP
# must be the configured IP address for one of the local interfaces.
ha.server=192.168.168.33:6001

# The interval at which slaves will pull updates from the master. Comment out
# the option to disable periodic pulling of updates. Unit is seconds.
ha.pull_interval=10

# Amount of slaves the master will try to push a transaction to upon commit
# (default is 1). The master will optimistically continue and not fail the
# transaction even if it fails to reach the push factor. Setting this to 0 will
# increase write performance when writing through master but could potentially
# lead to branched data (or loss of transaction) if the master goes down.
#ha.tx_push_factor=1

# Strategy the master will use when pushing data to slaves (if the push factor
# is greater than 0). There are two options available "fixed" (default) or
# "round_robin". Fixed will start by pushing to slaves ordered by server id
# (highest first) improving performance since the slaves only have to cache up
# one transaction at a time.
#ha.tx_push_strategy=fixed

# Policy for how to handle branched data.
#branched_data_policy=keep_all

# Clustering timeouts
# Default timeout.
#ha.default_timeout=5s

# How often heartbeat messages should be sent. Defaults to ha.default_timeout.
#ha.heartbeat_interval=5s

# Timeout for heartbeats between cluster members. Should be at least twice that of ha.heartbeat_interval.
#heartbeat_timeout=11s

/etc/haproxy/haproxy-neo4j.cfg

global
  daemon
  maxconn 384

defaults
  mode http
  timeout connect 5000ms
  timeout client 50000ms
  timeout server 50000ms

frontend http-in
  bind *:7777
  default_backend neo4j

backend neo4j
  option httpchk GET /db/manage/server/ha/available
  server s1 192.168.168.33:7474 maxconn 128 check
  server s2 192.168.168.34:7474 maxconn 128 check
  server s3 192.168.168.35:7474 maxconn 128 check

listen admin
  bind *:7770
  stats enable

yum install haproxy
haproxy -f /etc/haproxy/haproxy-neo4j.cfg

See: http://192.168.168.33:7770/haproxy?stats