Object Storage Service:Configure ossfs and perform mount operations

Specify account information

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

Use instance RAM roles

You can also mount a bucket by using ossfs based on a Resource Access Management (RAM) role of an Elastic Compute Service (ECS) instance. You can attach a RAM role to an ECS instance to access OSS from the instance by using temporary access credentials that are provided by Security Token Service (STS). STS temporary access credentials are automatically generated and updated. Applications can obtain STS temporary access credentials by using the instance metadata URL. An instance RAM role helps secure your AccessKey pair against leaks and enable fine-grained permission control and management. For more information about instance RAM roles, see Overview.

This section describes how to mount a bucket by using ossfs based on the EcsRamRoleOssTest instance RAM role:

1. Create a RAM role named EcsRamRoleOssTest.

   For more information, see Instance RAM roles.

2. Grant the RAM role permissions to access OSS resources.

   For more information, see Grant permissions to a RAM role. In this example, the AliyunOSSReadOnlyAccess policy is attached to the RAM role to grant read-only access to OSS. In your actual business application, you can attach a custom policy to the RAM role. For more information, see Create custom policies.

3. Attach the RAM role to the ECS instance.

   For more information, see Instance RAM roles.

4. Perform a mount operation by using ossfs based on the instance metadata URL.

   Note

   You can only access instance metadata in normal mode if you perform the mount operation by using ossfs based on the instance metadata URL. For more information, see Obtain instance metadata.

   1. Log on to the ECS instance.

   2. Include the -oram_role option in the mount operation to mount an OSS bucket.

      The following example mounts a bucket named Bucket1 in the China (Hangzhou) region at the /tmp/ossfs directory. In the command, 100.100.100.200 is the default IP address for the ECS instance metadata service.

      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

Mount a specific directory

ossfs bucket:/prefix mount_point -ourl=endpoint

When you mount a directory, make sure that the directory ${prefix}/ exists in the bucket. You can run the stat command of ossutil to check whether such a directory object exists.

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

Automatically mount a directory upon startup

1. Add information such as the bucket name, AccessKey ID, and AccessKey secret to the /etc/passwd-ossfs file and change the permissions of the file to 640.

   For more information, see Install ossfs.

2. Enable automatic mount upon startup.

   Note

   The following examples show how to enable automatic mount upon startup for common distributions and versions. For other distributions and versions, refer to the relevant documents to enable automatic mount upon startup.

   Enable automatic mount upon startup by using the fstab file for Ubuntu 14.04 or later and CentOS 6.5 or later

   1. Add the following line to the /etc/fstab file:

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

      Parameters:

      Parameter	Description
      bucket_name	The name of the bucket to mount.
      mount_point	The local directory on which you want to mount the bucket.
      url=url	The endpoint of the region in which the bucket is located.
      0 0	The options for the file system.

   2. Save the /etc/fstab file. Run the mount -a command. If no errors are reported, the settings are correctly configured.

   3. After you complete the preceding steps, automatic mount upon startup is enabled in Ubuntu 14.04 or later. For CentOS 6.5 or later, you must also run the following command:

      chkconfig netfs on

   Enable automatic mount upon 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 grant the execute permission to the ossfs script:

      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 mounted on the specified directory.

   3. Run the following command to start the ossfs script as a service which is automatically enabled upon startup:

      chkconfig ossfs on

   4. After you complete the preceding steps, ossfs automatically mounts the bucket upon startup.

Start ossfs by using Supervisor

1. Run the following command to install Supervisor:

   CentOS

   sudo yum install supervisor

   Ubuntu

   sudo apt-get install supervisor

2. Create an ossfs startup script.

   1. Run the following command to create a start_ossfs.sh file:

      mkdir /home/user1/ossfs_scripts

   2. Write the startup script.

      vi /home/user1/ossfs_scripts/start_ossfs.sh

      The following code is an example of start_ossfs.sh file content.

      # Unmount the bucket.
      fusermount -u /mnt/ossfs
      # Mount the 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 supervisord.conf file.

   Centos

   sudo vi /etc/supervisord.conf

   Ubuntu

   sudo vi /etc/supervisor/supervisord.conf

   Add the following content at the end of the file:

   [program:ossfs]
   command=bash /home/user1/ossfs_scripts/start_ossfs.sh
   logfile=/var/log/ossfs.log
   log_stdout=true
   log_stderr=true
   logfile_maxbytes=1MB
   logfile_backups=10

4. Run the following command to run Supervisor:

   supervisord

5. Check whether Supervisor runs as expected.

   1. Run the following command to check the Supervisor process:

      ps aux | grep supervisor

   2. Run the following command to check the ossfs process:

      ps aux | grep ossfs

      The following figure shows sample output, in which IDs such as 2044 and 2452 are the process IDs of ossfs.

      

   3. Run the following command to shut down the ossfs process:

      Important

      Do not use the killall command. If you run the killall command, the command sends the SIGTERM signal to stop the ossfs process. In this case, Supervisor does not restart the ossfs process.

      kill -9 processID

      After the ossfs process is shut down, Supervisor restarts the ossfs process.

   4. Run the following command to check the ossfs process:

      ps aux | grep ossfs

Enable log debugging

Unmount the mounted file system

You can unmount the OSS file system that has been mounted to the local disk by using the umount [path of the mount point] command.

The following code provides an example on how to unmount the file system mounted on /tmp/ossfs.

umount /tmp/ossfs