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Local Machine

This guide goes over how to run and test Alluxio on your local machine.

Requirements

The prerequisite for this part is that you have a version of Java 8 installed.

Download the binary distribution of Alluxio.

To run in standalone mode, do the following:

  • Create conf/alluxio-site.properties by copying conf/alluxio-site.properties.template

  • Set alluxio.master.hostname in conf/alluxio-site.properties to localhost (i.e., alluxio.master.hostname=localhost).

  • Set alluxio.master.mount.table.root.ufs in conf/alluxio-site.properties to a tmp directory in the local filesystem (e.g., alluxio.master.mount.table.root.ufs=/tmp).

  • Turn on remote login service so that ssh localhost can succeed. To avoid the need to repeatedly input the password, you can add the public SSH key for the host into ~/.ssh/authorized_keys. See this tutorial for more details.

Mount RAMFS file system

Run the below command to mount RAMFS file system.

$ ./bin/alluxio-mount.sh SudoMount

Format Alluxio Filesystem

NOTE: This step is only required when you run Alluxio for the first time. If you run this command for an existing Alluxio cluster, all previously stored data and metadata in Alluxio filesystem will be erased. However, data in under storage will not be changed.

$ ./bin/alluxio format

Start Alluxio Filesystem Locally

Simply run the following command to start Alluxio filesystem.

# If you have not mounted the ramdisk or want to remount it (ie. to change the size)
$ ./bin/alluxio-start.sh local SudoMount
# OR if you have already mounted the ramdisk
$ ./bin/alluxio-start.sh local

NOTE: On Linux, this command may require to input password to get sudo privileges in order to mount the RAMFS. If you do not want to type in the password every time, or you do not have sudo privileges, please read the alternative approaches in FAQ.

Verify Alluxio is running

To verify that Alluxio is running, visit http://localhost:19999, or see the log in the logs folder.

To run a more comprehensive sanity check:

$ ./bin/alluxio runTests

You can stop Alluxio any time by running:

$ ./bin/alluxio-stop.sh local

FAQ

Why is sudo privilege needed to start Alluxio on Linux?

By default, the Alluxio filesystem uses RAMFS as its in-memory data storage. On MacOS, it is fine for Alluxio to mount a RAMFS without being a super user. However, on Linux, it requires sudo privileges to perform mount (and the associated umount, mkdir and chmod operations).

Can I still try Alluxio on Linux without sudo privileges?

If you have no sudo privileges on Linux, for Alluxio Filesystem to work, it requires a RAMFS (e.g., /path/to/ramdisk) already mounted by the system admin and accessible for read/write-operations by the user. In this case you can specify the path in conf/alluxio-site.properties:

alluxio.worker.tieredstore.level0.alias=MEM
alluxio.worker.tieredstore.level0.dirs.path=/path/to/ramdisk

and then start Alluxio with NoMount option to use the above directory as its data storage:

$ ./bin/alluxio-start.sh local NoMount

Alternatively, you can also specify Linux tmpFS as the data storage. Tmpfs is a temporary file storage backed by memory (e.g., typically /dev/shm on Linux), but may use SWAP space and therefore provides less performance guarantees compared to ramfs. Similar to using a pre-mounted RAMFS, you can specify the tempfs path in conf/alluxio-site.properties:

alluxio.worker.tieredstore.level0.alias=MEM
alluxio.worker.tieredstore.level0.dirs.path=/dev/shm

followed by:

$ ./bin/alluxio-start.sh local NoMount

How can I avoid typing the password to run sudo?

Options:

  • Start Alluxio as a super user.

  • Add the user who starts Alluxio to the sudoers file.

  • Give limited sudo privileges to the running user (e.g., alluxio) by adding the following line to /etc/sudoers on Linux:

alluxio ALL=(ALL) NOPASSWD: /bin/mount * /mnt/ramdisk, /bin/umount */mnt/ramdisk, /bin/mkdir * /mnt/ramdisk, /bin/chmod * /mnt/ramdisk

This allows Linux user "alluxio" to mount, umount, mkdir and chmod (assume they are in /bin/) a specific path /mnt/ramdisk with sudo privileges without typing the password, but nothing else. See more detailed explanation about Sudoer User Specifications.

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