#Update test  
update_test is a tool to test TiDB rolling update.  
  
#How to run it  
Update test tool can be run by `run.sh`, the usages are as follow.   
 
    -h : Print help message.  
    -s <test-server-addresss> : Install TiDB cluster on <test-server-addresss>,default value is 127.0.0.1.  
    -o <old-version> : The old version TiDB cluster you want to insatll is <old-version>
    , default value is v2.0.3.  
    -n <new-version> : The version of TiDB cluster you want to update to is <new-version>
    , default value is latest version.  
    -a <old-tidb-commit-id> : You can update TiDB binary from specific commit id, by using <old-tidb-commit-id>.  
    -b <old-tikv-commit-id> : You can update TiKV binary from specific commit id, by using <old-tikv-commit-id>.  
    -c <old-pd-commit-id> : You can update PD binary from specific commit id, by using <old-pd-commit-id>.  
    -x <new-tidb-commit-id> : You can also update TiDB binary to specific commit id, by using <new-tidb-commit-id>.  
    -y <new-tikv-commit-id> : You can also update TiKV binary to specific commit id, by using <new-tikv-commit-id>.  
    -z <new-pd-commit-id> : You can also update PD binary to specific commit id, by using <new-pd-commit-id>.  
    -p Use this flag if you want use commit id on PR
  
#Example 1
     chmod +x ./run.sh
     ./run.sh -s 172.16.10.124 -o v2.0.0 -x fd80f19e898da7bef3287dc20e1eb9a02d1dfa4e
These commands will run update test tool and install TiDB cluster on 172.16.10.124, testing rolling update from v2.0.0 to commit id:fd80f19e898da7bef3287dc20e1eb9a02d1dfa4e.  

#Example 2  
     chmod +x ./run.sh  
     ./run.sh -o latest -a fd80f19e898da7bef3287dc20e1eb9a02d1dfa4e  
     -x 607a0f36d71d69f5bd459c12d87a46aeff0b2caa  
These commands will run update test tool and install TiDB cluster on 127.0.0.1, testing rolling update from the TiDB commit id: fd80f19e898da7bef3287dc20e1eb9a02d1dfa4e to commit id: 607a0f36d71d69f5bd459c12d87a46aeff0b2caa. Other components will be latest version.