Apsara File Storage NAS:Encryption in transit for NFS file systems

How it works

The NAS client defines a type of network file system (NFS) called alinas. The NFS is compatible with the standard form of the mount command. If you specify the tls parameter when you mount an alinas NFS on an ECS instance, the NAS client starts a process named stunnel. The process forwards and encrypts access requests from the ECS instance to the NAS server. The process also triggers a backend process named aliyun-alinas-mount-watchdog to ensure the availability of the stunnel process.

Usage notes

• The encryption in transit feature applies only to General-purpose NFS file systems.

• Operating systems supported by the NAS client

  Operating system	Version
  Alibaba Cloud Linux	Alibaba Cloud 2.1903 64-bit
  Red Hat	Red Hat Enterprise Linux 7.x 64-bit Red Hat Enterprise Linux 8.x 64-bit
  CentOS	CentOS 7.x 64-bit CentOS 8.x 64-bit
  Ubuntu	Ubuntu 16.04 64-bit Ubuntu 18.04 64-bit Ubuntu 20.04 64-bit
  Debian	Debian 9.x 64-bit Debian 10.x 64-bit

• Performance loss

  Compared with a file system for which you disable encryption in transit, a file system for which you enable encryption in transit can be accessed with a 10% more latency and 10% less IOPS.

• Usage notes of the NAS client

  • The NAS client uses the stunnel process as a TLS encryption wrapper. For high-throughput applications, the stunnel process consumes a large number of CPU resources to perform encryption and decryption. In extreme cases, each mount operation consumes the capacity of an entire core.

  • The NAS client requires a third-party certificate to encrypt data in transit. The certificate must be updated at regular intervals. NAS sends update notifications to you one month in advance by using emails and internal messages. After you receive these notifications, you must update the aliyun-alinas-utils tool at your earliest opportunity. Otherwise, the mounted NAS file system stops responding after the certificate expires.

  • If you use the NAS client, the /etc/hosts file of the ECS instances within your Alibaba Cloud account is modified. Therefore, when you mount a file system, the new mount target is written to the /etc/hosts file. When you unmount the file system, the mount target is deleted from the file.

  • When the NAS client uses the stunnel process as a TLS encryption wrapper, the stunnel process listens on an IP address from 127.0.1.1 to 127.0.255.254 on port 12049. You must make sure that IP addresses and port are available.

    You can run the ss -ant | grep -w 12049 command to check whether the port is occupied. If no value is returned, the port is available. If the port is occupied, modify the configuration file. For more information about how to modify the configuration file of the NAS client, see Troubleshooting in this topic.

Supported regions

The encryption in transit feature is available in all regions of the Alibaba Cloud public cloud, and all regions of Alibaba Finance Cloud except China South 1 Finance.

Step 1: Download and install the NAS client

1. Download the NAS client.

   • Alibaba Cloud Linux

     wget https://aliyun-encryption.oss-cn-beijing.aliyuncs.com/aliyun-alinas-utils-1.0-1.al7.noarch.rpm

   • Red Hat Enterprise Linux 7.x and CentOS 7.x

     wget https://aliyun-encryption.oss-cn-beijing.aliyuncs.com/aliyun-alinas-utils-1.0-1.el7.noarch.rpm

   • Red Hat Enterprise Linux 8.x and CentOS 8.x

     wget https://aliyun-encryption.oss-cn-beijing.aliyuncs.com/aliyun-alinas-utils-1.0-1.el8.noarch.rpm

   • Ubuntu and Debian

     wget https://aliyun-encryption.oss-cn-beijing.aliyuncs.com/aliyun-alinas-utils-1.0-1.deb

2. Install the NAS client.

   • Alibaba Cloud Linux and CentOS

     sudo yum install aliyun-alinas-utils-*.rpm

   • Red Hat Enterprise Linux

     sudo yum --disablerepo=rhui-rhel-7-server-rhui-extras-debug-rpms install aliyun-alinas-utils-*.rpm

   • Ubuntu and Debian

     sudo apt update

     sudo dpkg -i aliyun-alinas-utils-*.deb

     sudo apt-get install -f

     sudo dpkg -i aliyun-alinas-utils-*.deb

3. Check whether the NAS client is installed.

   which mount.alinas

   The information in the following figure indicates a successful installation.

Step 2: Mount a NFS file system with encryption in transit enabled

1. Mount the NFS file system.

   • NFSv3 protocol

     sudo mount -t alinas -o tls,vers=3 file-system-id.region.nas.aliyuncs.com:/ /mnt

   • NFSv4.0 protocol

     sudo mount -t alinas -o tls,vers=4.0 file-system-id.region.nas.aliyuncs.com:/ /mnt

   The following table lists the parameters that are used in the mount command.

   Note

   The NAS client tool uses the parameters that can ensure the optimal performance when it mounts the file system. Therefore, you do not need to set the parameters by yourself. For more information, see the mount parameters described in Mount an NFS file system on a Linux ECS instance.

   Parameter	Description
   file-system-id.region.nas.aliyuncs.com:/ /mnt	The command syntax is <Domain name of a mount target>:<Name of a shared directory><Path of a mount directory>. You must replace the domain name, directory name, and directory path with their actual values. Domain name of a mount target: To view the domain name, perform the following steps: Log on to the NAS console. In the left-side navigation pane, click File System List. On the page that appears, find the file system that you want to manage and click Manage in the Actions column. On the page that appears, click Mount Targets. On the tab that appears, view the domain name of the mount target. For more information, see View the domain name of a mount target. Name of a shared directory: specifies the root directory / or a subdirectory. If you specify a subdirectory such as /share, make sure that the subdirectory exists in the NAS file system. Path of a mount directory: specifies a subdirectory such as /mnt of a Linux ECS instance. Make sure that the subdirectory exists in the local file system.
   vers	The protocol version of the file system. vers=3: Uses NFSv3 to mount the file system. vers=4: Uses NFSv4.0 to mount the file system.
   tls	Enables TLS.

2. Run the mount -l command to view the mount result.

   If an output similar to the following example appears, the mount is successful.

   After the file system is mounted, you can run the df -h command to view the capacity of the file system.

3. Optional. Configure automatic mounting at startup.

   When you restart the ECS instance to which the file system is mounted, the information about all the mounted file systems may be lost. To prevent the loss of such information, you can edit the /etc/fstab configuration file in the Linux ECS instance to enable automatic mount of NFS file system at startup.

   1. Open the /etc/fstab configuration file to add mounting configurations.

      file-system-id.region.nas.aliyuncs.com:/ /mnt alinas _netdev,tls 0 0

      For more information, see Mount an NFS file system on a Linux ECS instance. The following table describes the parameters that are not included in the preceding table.

      Parameter	Description
      _netdev	Prevents automatic mounting before the network is connected.
      0 (the first value after tls)	Specifies whether to back up the file system by running the dump command. A non-zero value indicates that a file system is backed up. The default value is 0 for NAS file systems.
      0 (the second value after tls)	Specifies the order in which the fsck command checks a file system at startup. The default value is 0 for NAS file systems. The default value 0 indicates that the fsck command is not run at startup.

   2. Run the reboot command to restart the ECS instance.

      If you restart the ECS instance, services are interrupted. We recommend that you perform the operation during off-peak hours.

      Note

      Before you restart the ECS instance, make sure that the manual mount is successful. Otherwise, the ECS instance may fail to restart. If automatic mounting is enabled, after the ECS instance is restarted, you can run the df -h command to view the NAS file systems that are mounted.

NAS client logs

You can locate the mount error by opening the log file of the NAS client in the /var/log/aliyun/alinas/ directory. You can also modify the parameters in the log configuration file in the /etc/aliyun/alinas/alinas-utils.conf directory to configure the NAS client log. After you modify the configuration file, run the sudo service aliyun-alinas-mount-watchdog restart command. Then, the backend watchdog is restarted.

Troubleshooting

• Issue

  When the file system is being mounted, the following error message is returned:

• Cause

  The IP address or port 12049 on which stunnel listens is used by other processes. As a result, the file system fails to be mounted.

• Solution

  • Solution 1: Find and terminate the process that uses port 12049. Then, mount the file system again.

  • Solution 2: Edit the configuration file of the client tool in the /etc/aliyun/alinas/alinas-utils.conf directory. Change the value of the proxy_port parameter to an unused port number. Then, mount the file system again.