Advanced configurations

Configure the account information

When you use ossfs to access Object Storage Service (OSS) buckets, you must configure your account information including your AccessKey ID and AccessKey secret. The account information must be written to the account configuration file in a specific format. ossfs obtains the account information in the $bucket_name:$access_key_id:$access_key_secret format from the account configuration file.

Use instance RAM roles

In Elastic Compute Service (ECS), you can use ossfs based on instance Resource Access Management (RAM) roles. You can bind a RAM role to an ECS instance to access OSS from the instance by using Security Token Service (STS) temporary credentials. STS temporary credentials are automatically generated and updated. Applications can obtain the STS temporary credentials by using the instance metadata URL. RAM helps protect the security of your AccessKey pair and facilitates fine-grained permission control and management. For more information about instance RAM roles, see Overview.

The following section describes how to use ossfs by using the EcsRamRoleOssTest instance RAM role:

1. Create a RAM role named EcsRamRoleOssTest.
   For more information about how to create a RAM role, see Step 1: Create an instance RAM role.
2. Grant the RAM role permissions to access OSS resources.
   For more information about how to grant permissions to a RAM role, see Grant permissions to a RAM role. In this example, the RAM role is granted the AliyunOSSReadOnlyAccess permission. You can customize the permission. For more information, see Create a custom policy.
3. Bind an ECS instance to the RAM role.
   For more information, see Step 3: Bind the instance RAM role.
4. Use ossfs based on the instance metadata URL.
   1. Log on to the ECS instance.
   2. Use ossfs. Add the -oram_role option.
      The bucket named Bucket1 in the China (Hangzhou) region is used in the example:

      ossfs bucket1 /tmp/ossfs -ourl=http://oss-cn-hangzhou.aliyuncs.com -oram_role=http://100.100.100.200/latest/meta-data/ram/security-credentials/EcsRamRoleOssTest

Configure access permissions

Attach a specific directory

ossfs bucket:/prefix mount_point -ourl=endpoint

When you run this command, make sure that an object named ${prefix}/ exists in the bucket. You can run the stat command of ossutil to check whether the object exists.

ossfs bucket-ossfs-test:/folder /tmp/ossfs-folder -ourl=http://oss-cn-hangzhou.aliyuncs.com

Attach a directory on startup

1. Write the bucket name, AccessKey ID, and AccessKey secret to the /etc/passwd-ossfs file, and change the permission on the file to 640.
   For more information, see Installation.
2. Enable automatic mount on startup.
   The method to enable automatic mount on startup varies with the version of your operating system.

   • Enable automatic mount on startup by using the fstab file for Ubuntu 14.04 and CentOS 6.5
     1. Add the following command to the /etc/fstab file:

        ossfs#bucket_name mount_point fuse _netdev,url=url,allow_other 0 0

     2. Save the /etc/fstab file. Run the mount -a command. The settings are correct if no errors are reported.
     3. After you complete the preceding operations, automatic mount on startup is enabled in Ubuntu 14.04. For CentOS 6.5, you must also run the following command:

        chkconfig netfs on

   • Enable automatic mount on startup by using the script for CentOS 7.0 or later
     1. Create the ossfs file in the /etc/init.d/ directory, and copy the content of the template to this file. Replace your_xxx with your actual information.
     2. Run the following command to allow the ossfs script to be executed:

        chmod a+x /etc/init.d/ossfs

        After the preceding command is run, you can execute the script. If the content of the script is correct, the OSS bucket is attached to the specified directory.
     3. Run the following command to start the ossfs script as a service which is automatically enabled on startup:

        chkconfig ossfs on

     4. After you complete the preceding operations, automatic mount on startup is enabled for ossfs.

Start ossfs by using Supervisor

Supervisor is a universal process management program of Python. Supervisor can turn a general command-line process into a background daemon and monitor the process. Supervisor automatically restarts the process when the process stops unexpectedly. Perform the following steps to start ossfs by using Supervisor:

1. Install Supervisor.
   • CentOS

     yum install supervisor

   • Ubuntu

     sudo apt-get install supervisor

2. Create an ossfs startup script.
   1. Create the start_ossfs.sh file.

      mkdir /root/ossfs_scripts
      vi /root/ossfs_scripts/start_ossfs.sh

   2. Write the startup script.

      # Remove the mount point.
      fusermount -u /mnt/ossfs
      # Attach the OSS bucket again. You must use the -f parameter to run ossfs on the frontend. 
      exec ossfs bucket_name mount_point -ourl=endpoint -f

3. Edit the /etc/supervisor/supervisord.conf file. Add the following content to the end of the file:

   [program:ossfs]
   command=bash /root/ossfs_scripts/start_ossfs.sh
   logfile=/var/log/ossfs.log
   log_stdout=true
   log_stderr=true
   logfile_maxbytes=1MB
   logfile_backups=10

4. Run Supervisor.

   supervisord

5. Verify whether Supervisor runs properly.

   ps aux | grep supervisor # The Supervisor process is displayed. 
   ps aux | grep ossfs # The ossfs process is displayed. 
   kill -9 ossfs # Terminate the ossfs process. Supervisor restarts ossfs. Do not run the killall command because this command sends the SIGTERM signal to terminate the ossfs process. In this case, Supervisor will not restart ossfs. 
   ps aux | grep ossfs # The ossfs process is displayed. 

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