brick_ops.md

Brick Ops:

The code can be found at brick_ops.py

1. add_brick
   This method is used to add a brick or a set of bricks to the volume.

    Args:
    	1. volname (str): The volume in which the brick has to be added.
    	2. brick_str (list): String of brick cmd created by form_brick_cmd function.
    	3. node (str): The node on which the command is to be run.
    	4. force (bool): If set to True will add force in the command being executed.
    	5. replica count (int): Optional parameter with default value of None.
    	6. arbiter_count (int): Optional parameter with default value of None.
    Returns:
    	A dictionary consisting                                        
        1. Flag : Flag to check if connection failed                 
        2. msg : message                                             
        3. error_msg: error message                                  
        4. error_code: error code returned                           
        5. cmd : command that got executed                           
        6. node : node on which the command got executed
    Example:
    	self.add_brick(self.vol_name, brick_cmd, self.server_list[0],
                       replica_count=3)
   

2. remove_brick
   Remove brick does the opposite of add_brick operation and that is it removes existing brick or bricks from the volume. It has almost the same set of arguments apart from option which stores the remove brick options like start, commit, stop etc:

    Args:
    	1. node (str): Node on which the command has to be executed.
    	2. volname (str): The volume from which brick or a set of bricks have to be removed.
    	3. brick_list (list): The list of bricks to be removed.
    	4. option (str): Remove brick options: <start|stop|status|commit|force>
    	5. replica_count (int): Optional argument with default value of None. This represent the desired replica count after the removal of the said bricks.
    Returns:
    	A dictionary consisting                                        
        1. Flag : Flag to check if connection failed                 
        2. msg : message                                             
        3. error_msg: error message                                  
        4. error_code: error code returned                           
        5. cmd : command that got executed                           
        6. node : node on which the command got executed
    Example:
    	self.remove_brick(self.server_list[0], self.vol_name, self.brick_list, option)
   

3. replace_brick
   This function replaces one brick with another brick or in other words, source brick with destination brick. For now, the arguments it takes include:

    Args:
    	1. node (str): The node on which the command has to be executed
    	2. volname (str): The volume on which the bricks have to be replaced.
    	3. src_brick (str) : The source brick name
    	4. dest_brick (str) : The destination brick name
    Returns:
    	A dictionary consisting                                        
        1. Flag : Flag to check if connection failed                 
        2. msg : message                                             
        3. error_msg: error message                                  
        4. error_code: error code returned                           
        5. cmd : command that got executed                           
        6. node : node on which the command got executed
    Example:
    	self.replace_brick(self.server_list[0], self.vol_name, src_brick, dest_brick)
   

4. reset-brick
   This function resets a brick in the volume. Reset-brick is useful in case a disk goes bad etc. It provides support to reformat the disk that the brick represents in the volume

    Args:
    	1. node (str) : Node on which the command has to be executed
    	2. volname (str) : Name of the volume on which the brick has to be reset
    	3. src_brick (str) : Name of the source brick
    	4. dst_brick (str) : Name of the destination brick
    	5. option (str) : Options for reset brick : start | commit | force
    Returns:
    	A dictionary consisting                                        
        1. Flag : Flag to check if connection failed                 
        2. msg : message                                             
        3. error_msg: error message                                  
        4. error_code: error code returned                           
        5. cmd : command that got executed                           
        6. node : node on which the command got executed
    Example:
    	self.reset_brick(self.server_list[0], self.vol_name, src_brick, option, dest_brick)
   

5. form_brick_cmd
   This function helps in creating the brick command from the brick paths. It requires the following arguments:

    Args:
    	1. server_list (list): List of servers
    	2. brick_root (dict) : List of brick roots
    	3. volname (str) : Name of the volume
    	4. mul_fac (int) : Stores the number of bricks needed to form the brick command
    	5. add_flag (bool): Optional parameter with default value of False. When set, the brick cmd creation will happen with respect to brick addition.
    Returns:
    	A tuple containing
    		1. brick_dict (dict) : Dictionary of server and their corresponding brick roots.
    		2. brick_cmd (str) : Command which contains the brick paths.
    Example:
    	self.form_brick_cmd(self.server_list, self.brick_root, self.vol_name, mul_factor, True)
   

6. are_bricks_offline
   This function checks if the given list of bricks are offline.

    Args:
        1. volname (str) : Volume name
    	2. bricks_list (list) : list of bricks to check
    	3. node (str) : the node on which comparison has to be done
    	4. strict (bool) : To check strictly if all bricks are offline or atleast one brick is offline.
    Returns:
    	boolean value: True, if bricks are offline else False
    Example:
    	redant.are_bricks_offline(self.vol_name, bricks_list, self.server_list[0])
   

7. check_if_bricks_list_changed
   Function checks if the bricks list changed. Basically, compares the bricks list with the bricks attained from volume info.

    Args:
    	1. bricks_list (list): list of bricks
    	2. volname (str): Name of volume
    	3. node (str): Node on which to execute vol info
   
    Returns:
    	bool: True if list is changed else False
    Example:
    	redant.check_if_bricks_list_changed(bricks_list, self.vol_name, self.server_list[0])
   

8. get_all_bricks
   Function to get the list of all the bricks of the specified volume.

    Args:
    	1. volname (str): Name of the volume
    	2. node (str): The node wherein the command is executed.
    Returns:
    	List of all bricks else None on failure.
    Example:
    	self.get_all_bricks(self.vol_name, self.server_list[0])
   

9. get_online_bricks_list
   Function to get the list of all bricks which are online.

    Args:
    	1. volname (str): Name of the volume
    	2. node (str): Noe wherein the command is to be exexuted.
    Returns:
    	List of bricks which are online in the format of server:brick_path on failure, if returns None
    Example:
    	online_list = self.get_online_bricks_list(self.vol_name, self.server_list[2])
   

10. get_offline_bricks_list
    Function to get the list of all bricks which are offline.

    Args:
    	1. volname (str): Name of the volume
    	2. node (str): Noe wherein the command is to be exexuted.
    Returns:
    	List of bricks which are offline in the format of server:brick_path on failure, if returns None
    Example:
    	offline_list = self.get_offline_bricks_list(self.vol_name, self.server_list[2])
    

11. bring_bricks_offline
    Function to bring the given seet of bricks offline.

    Args:
    	1. volname (str): Name of the volume to which these bricks belong to.
    	2. brick_list (list): The list of bricks which are to be brought offline.
    	3. timeout (int): optional parameter with default value as 100. The function waits for these many seconds for the bricks to go offline at max.
    Returns:
    	True if bricks have been successfully brough offline else False.
    Example:
    	self.bring_bricks_offline(self.volname, self.brick_list[2:4])
    

12. bring_bricks_online
    Function to bring the given seet of bricks online.

    Args:
    	1. volname (str): Name of the volume to which these bricks belong to.
    	2. brick_list (list): The list of bricks which are to be brought online.
    	3. timeout (int): optional parameter with default value as 100. The function waits for these many seconds for the bricks to come online at max.
    Returns:
    	True if bricks have been successfully brough online else False.
    Example:
    	self.bring_bricks_offline(self.volname, self.brick_list[2:4])
    

13. wait_for_bricks_to_go_offline
    Function to wait till a given set of bricks go offline

    Args:
    	1. volname (str): Name of the volume whose bricks are to be noticed.
    	2. brick_list (list): The list of bricks which are expected to go offline.
    	3. timeout (int): optional parameter with default value as 100. The function waits for these many seconds for the bricks to go offline at max.
    Returns:
    	True if bricks have been successfully gone offline else False.
    Example:
    	self.wait_for_bricks_to_go_offline(self.vol_name, self.brick_list, timeout)
    

14. wait_for_bricks_to_come_online
    Function to wait till a given set of bricks come online

    Args:
    	1. volname (str): Name of the volume whose bricks are to be noticed.
    	2. server_list (str): The list of nodes wherein the volume is hosted.
    	2. brick_list (list): The list of bricks which are expected to come online.
    	3. timeout (int): optional parameter with default value as 100. The function waits for these many seconds for the bricks to come online at max.
    Returns:
    	True if bricks have been successfully come online else False.
    Example:
    	self.wait_for_bricks_to_come_online(self.volname, self.server_list, self.brick_list, timeout)
    

15. replace_brick_from_volume
    Function to replace a faulty brick from a volume.

    Args:
        volname (str): Volume in which the brick has to be replaced
        node (str): Node on which command has to be executed
        server_list (list): List of servers in the cluster
    
    Optional:
        src_brick (str): Brick to be replaced
        dst_brick (str): New brick which will replace the old one
        delete_brick (bool): True, if the old brick should be deleted otherwise False. (Default is True)
    
    Returns:
        bool: True if the replace brick operation was successful,
              False if the operation failed.
    
    Example:
    	redant.replace_brick_from_volume(self.vol_name,
    									 self.server_list[0],
    									 self.server_list,
    									 brick_to_replace,
    									 new_brick_to_replace)
    

16. are_bricks_online
    Function to check if the given list of bricks are online.

    Args:
        volname (str) : Volume name
        bricks_list (list) : list of bricks to check
        node (str) : the node on which comparison has to be done
        strict (bool) : To check strictly if all bricks are online
    Returns:
        boolean value: True, if bricks are online
                       False, if offline
    
    Example:
    	redant.are_bricks_online(self.vol_name, bricks_list, self.server_list[0])
    

17. get_brick_processes_count
    This function helps in getting the brick process count for a given node.

    Args:
        node (str): Node on which brick process has to be counted.
    
    Returns:
        int: Number of brick processes running on the node.
        None: If the command fails to execute.
    
    Example:
    	count = redant.get_brick_processes_count(server)