Level 3: node quota and other commands

The first 3 Turn off ： Node quota and other commands

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• Mission requirements
• Refer to the answer
• Comment on 20

• Task description
• Related knowledge
  • quota（ The quota ）
  • Other commands
• Programming requirements
• Test instructions

Task description

Our mission ： Have a good command of ZooKeeper Quota for （quota ） Setting method and other commands of node .

Related knowledge

In order to complete this mission , You need to master ：1.ZooKeeper Server startup and client startup ,2. Command line basic operations ,3.ZooKeeper Node quota method and basic operation .

quota（ The quota ）

ZooKeeper The quota mechanism is used to manage the data size of the current node and the number of child nodes . You can set quota limits on nodes , If the configuration limit is exceeded ,ZooKeeper Will be in log Print in log WARN journal , But it doesn't stop the behavior operation .

ZooKeeper The quota is stored in /zookeeper/quota The next path . Can pass ZooKeeper client APIs perhaps ZooKeeper Java Shell To carry out set,list,delete The quota . With /zoo1 Node as an example , explain 3 How to use commands .

• First, list the quota of the current node , Use the following command ：

  1. listquota /zoo1

  

  You can find ,zoo1 The node has no quota set . Set node quota usage setquota command . for example , Set the quota of this node to 3, Use the following command ：

  1. setquota -n 3 /zoo1

  

  -n Indicates setting the node number limit , It means /zoo1 The number of nodes under the path is limited to 3（ Include this node ）; -b Indicates setting the byte size limit of node data .

  Use listquota Command to view the current node quota , Same as setting quota value .

  

  ZooKeeper Use a more gentle way , If the configuration limit is exceeded ,ZooKeeper Will be in log Print in log WARN journal , It does not stop the behavior operation . for example , establish /zoo1 Of 3 Child node , Use the following command ：

  1. create /zoo1/child1 ""
  2. create /zoo1/child2 ""
  3. create /zoo1/child3 ""

  

  When a node is created , From the log （ Or server front end ） Get the information shown in the figure below ：

  

• Delete node quota usage delquota command . for example , Delete /zoo1 The number of nodes is limited , Use the following command ：

  1. delquota /zoo1

  

Other commands

• ls2: List the details of the current node .

  

• sync： When reading a node , It should be done first sync Method , Make the connection of the read operation connected ZooKeeper Examples can be compared with leader To synchronize , So that you can read the latest content .

  

• history： Before listing 10 Historical orders .

  

• redo： Reexecution of N Orders .

  

Programming requirements

This task is to use the command line , Do the following ：

• Turn on ZooKeeper The server .

• Using client （zkCli.sh） Connect to the client （IP：127.0.0.1, Port number ：2181）.

• establish /test_quota Persistent node （ Node data is empty ）.

• Set up /test_quota The number of path nodes is limited to 3.

• Disconnect the client （zkCli.sh） Connect with customer service terminal .

Test instructions

The test of this level needs to be completed by the user under the command line on the right , The user only needs to directly operate the commands to be completed under the command line on the right , Then click the evaluation button , The platform will automatically verify whether the user checks the results as required .

Start your mission , wish you success ！