Class: ZK::Server::Config

Inherits:
Object
  • Object
show all
Defined in:
lib/zk-server/config.rb

Overview

Note that this supports all of the 3.3.5 options, but will not do any sanity checking for you. All options specifyable here (especially those that require directories to be created outside of #base_dir) may not be handled properly by Base and subclasses.

Constant Summary collapse

DEFAULT_JVM_FLAGS = 
%w[
  -server
  -Xmx256m
  -Dzookeeper.serverCnxnFactory=org.apache.zookeeper.server.NettyServerCnxnFactory
].freeze
DEFAULT_JMX_ARGS =

the com.sun.managemnt.jmxremote.port arg will be filled in dynamically based on the #jmx_port value

%w[
  -Dcom.sun.management.jmxremote=true
  -Dcom.sun.management.jmxremote.local.only=false
  -Dcom.sun.management.jmxremote.authenticate=false
  -Dcom.sun.management.jmxremote.ssl=false
].freeze
ZOO_MAIN = 
'org.apache.zookeeper.server.quorum.QuorumPeerMain'.freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ Config

Returns a new instance of Config.



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# File 'lib/zk-server/config.rb', line 202

def initialize(opts={})
  $stderr.puts "#{self.class}#initialize #{opts.inspect}" 
  @base_dir     = self.class.default_base_dir
  @zoo_cfg_hash = {}
  @tick_time    = 2000
  @client_port  = 2181
  @snap_count   = nil
  @force_sync   = nil
  @jmx_port     = 22222
  @enable_jmx   = false
  @jvm_flags    = DEFAULT_JVM_FLAGS.dup
  @myid         = 1
  @init_limit   = 5
  @sync_limit   = 2

  @max_client_cnxns = 100

  opts.each { |k,v| __send__(:"#{k}=", v) }
end

Instance Attribute Details

#base_dir ⇒ Object

The top level directory we will store all of our data under. used as the basis for all other path generation. Defaults to File.join(Dir.getwd, 'zookeeper')



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# File 'lib/zk-server/config.rb', line 29

def base_dir
  @base_dir
end

#client_port ⇒ Object Also known as: port

what port should the server listen on for connections? (default 2181)



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# File 'lib/zk-server/config.rb', line 60

def client_port
  @client_port
end

#client_port_address ⇒ Object

default: nil

the address (ipv4, ipv6 or hostname) to listen for client connections; that is, the address that clients attempt to connect to. This is optional, by default we bind in such a way that any connection to the clientPort for any address/interface/nic on the server will be accepted.



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# File 'lib/zk-server/config.rb', line 138

def client_port_address
  @client_port_address
end

#cnx_timeout ⇒ Object

default: nil

by default this is not specified

Sets the timeout value for opening connections for leader election notifications.



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# File 'lib/zk-server/config.rb', line 173

def cnx_timeout
  @cnx_timeout
end

#data_dir=(value) ⇒ Object

defaults to #{base_dir}/data. use this to override the default

the location where ZooKeeper will store the in-memory database snapshots and, unless specified otherwise, the transaction log of updates to the database.

be aware that the Base class will not create any directories but #base_dir.



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# File 'lib/zk-server/config.rb', line 40

def data_dir=(value)
  @data_dir = value
end

#data_log_dir ⇒ Object

defaults to nil, and zookeeper will just use the default value (being the same as #data_dir

This option will direct the machine to write the transaction log to the dataLogDir rather than the dataDir. This allows a dedicated log device to be used, and helps avoid competition between logging and snaphots.



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# File 'lib/zk-server/config.rb', line 49

def data_log_dir
  @data_log_dir
end

#enable_jmx ⇒ Object

if truthy, will enable jmx (defaults to false) note that our defualt jmx config has all security and auth turned off if you want to customize this, then use jvm_flags and set this to false



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# File 'lib/zk-server/config.rb', line 188

def enable_jmx
  @enable_jmx
end

#force_sync ⇒ Object

This value can make testing go faster, as zookeeper doesn't have to issue an fsync() call for each snapshot write. It is however DANGEROUS if you care about the data. (I set it to false for running tests)

if true: 'yes', false: 'no', nil not specified in the config

default: no value set



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# File 'lib/zk-server/config.rb', line 120

def force_sync
  @force_sync
end

#global_outstanding_limit ⇒ Object

default is nil, and will not be specified in the config

Clients can submit requests faster than ZooKeeper can process them, especially if there are a lot of clients. To prevent ZooKeeper from running out of memory due to queued requests, ZooKeeper will throttle clients so that there is no more than globalOutstandingLimit outstanding requests in the system. The default limit is 1,000.



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# File 'lib/zk-server/config.rb', line 81

def global_outstanding_limit
  @global_outstanding_limit
end

#init_limit ⇒ Object

necessary for cluster nodes (default 5)

from the zookeeper admin guide:

Amount of time, in ticks (see tickTime), to allow followers to connect and sync to a leader. Increased this value as needed, if the amount of data managed by ZooKeeper is large.



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# File 'lib/zk-server/config.rb', line 90

def init_limit
  @init_limit
end

#jmx_port ⇒ Object

default jmx port is 22222



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# File 'lib/zk-server/config.rb', line 191

def jmx_port
  @jmx_port
end

#jvm_flags ⇒ Object

array to which additional JVM flags should be added

default is DEEFAULT_JVM_FLAGS



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# File 'lib/zk-server/config.rb', line 196

def jvm_flags
  @jvm_flags
end

#leader_serves ⇒ Object

default: nil

If true, the value 'yes' will be used for this value, false will write 'no' to the config file. The default (nil) is not to specify a value in the config.

Leader accepts client connections. Default value is "yes". The leader machine coordinates updates. For higher update throughput at thes slight expense of read throughput the leader can be configured to not accept clients and focus on coordination. The default to this option is yes, which means that a leader will accept client connections



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# File 'lib/zk-server/config.rb', line 164

def leader_serves
  @leader_serves
end

#max_client_cnxns ⇒ Object

maximum number of client connections (defaults to 100)



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# File 'lib/zk-server/config.rb', line 65

def max_client_cnxns
  @max_client_cnxns
end

#max_session_timeout ⇒ Object

default: nil

the maximum session timeout in milliseconds that the server will allow the client to negotiate. Defaults to 20 times the tickTime.



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# File 'lib/zk-server/config.rb', line 151

def max_session_timeout
  @max_session_timeout
end

#min_session_timeout ⇒ Object

default: nil

the minimum session timeout in milliseconds that the server will allow the client to negotiate. Defaults to 2 times the tickTime



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# File 'lib/zk-server/config.rb', line 145

def min_session_timeout
  @min_session_timeout
end

#myid ⇒ Object

what cluster id should this zookeeper use for itself? (default 1)



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# File 'lib/zk-server/config.rb', line 71

def myid
  @myid
end

#pre_alloc_size ⇒ Object

default: nil

To avoid seeks ZooKeeper allocates space in the transaction log file in blocks of preAllocSize kilobytes. The default block size is 64M. One reason for changing the size of the blocks is to reduce the block size if snapshots are taken more often. (Also, see snapCount).



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# File 'lib/zk-server/config.rb', line 128

def pre_alloc_size
  @pre_alloc_size
end

#skip_acl ⇒ Object

default: nil

if true: 'yes', false: 'no', nil not specified in the config

this is listed as a DANGEROUS setting

Skips ACL checks. This results in a boost in throughput, but opens up full access to the data tree to everyone.



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# File 'lib/zk-server/config.rb', line 183

def skip_acl
  @skip_acl
end

#snap_count ⇒ Object

from the admin guide

ZooKeeper logs transactions to a transaction log. After snapCount transactions are written to a log file a snapshot is started and a new transaction log file is created. The default snapCount is 100,000.

For testing, to speed up disk IO, I generally set this to 1_000_000 and force_sync to false. YMMV, understand what this does before messing with it if you care about your data.

default: unset



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# File 'lib/zk-server/config.rb', line 111

def snap_count
  @snap_count
end

#sync_limit ⇒ Object

necessary for cluster nodes (default 2)

Amount of time, in ticks (see tickTime), to allow followers to sync with ZooKeeper. If followers fall too far behind a leader, they will be dropped.



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# File 'lib/zk-server/config.rb', line 98

def sync_limit
  @sync_limit
end

#tick_time ⇒ Object

defaults to 2000



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# File 'lib/zk-server/config.rb', line 68

def tick_time
  @tick_time
end

#zoo_cfg_hash ⇒ Object

a hash that will be used to provide extra values for the zoo.cfg file. keys are written as-is to the file, so they should be camel-cased.

dataDir will be set relative to #base_dir and clientPort will either use the default of 2181, or can be adjusted by #client_port=



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# File 'lib/zk-server/config.rb', line 57

def zoo_cfg_hash
  @zoo_cfg_hash
end

Class Method Details

.default_base_dir ⇒ Object 



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# File 'lib/zk-server/config.rb', line 198

def self.default_base_dir
  File.join(Dir.getwd, 'zookeeper')
end

Instance Method Details

#to_config_file_str ⇒ Object

renders this config as a string that can be written to zoo.cfg



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# File 'lib/zk-server/config.rb', line 270

def to_config_file_str
  config = {
    'dataDir'                 => data_dir,
    'skipACL'                 => skip_acl,
    'tickTime'                => tick_time,
    'initLimit'               => init_limit,
    'syncLimit'               => sync_limit,
    'forceSync'               => force_sync,
    'snapCount'               => snap_count,
    'clientPort'              => client_port,
    'dataLogDir'              => data_log_dir,
    'preAllocSize'            => pre_alloc_size,
    'leaderServes'            => leader_serves,
    'maxClientCnxns'          => max_client_cnxns,
    'clientPortAddress'       => client_port_address,
    'minSessionTimeout'       => min_session_timeout,
    'maxSessionTimeout'       => max_session_timeout,
    'globalOutstandingLimit'  => global_outstanding_limit,
  }
  
  config = config.merge(zoo_cfg_hash)

  config.delete_if { |k,v| v.nil? }

  %w[leaderServes skipACL forceSync].each do |yorn_key|
    if config.has_key?(yorn_key)
      config[yorn_key] = config[yorn_key] ? 'yes' : 'no'
    end
  end

  config.sort.map {|kv| kv.join("=") }.join("\n")
end