Easing the File Download Process on SRX Series Services Gateways for the Branch

Transcription

1 APPLICATION NOTE Smart Download Manager Easing the File Download Process on SRX Series Services Gateways for the Branch Copyright 2012, Juniper Networks, Inc. 1

2 Table of Contents Introduction...3 Scope...3 Design Considerations...3 Hardware Requirements...3 Software Requirements...3 Description and Deployment Scenario...3 How to Use...3 Create a New Download Instance...3 Pause a Running Download Instance... 4 Resume Paused or Error Download... 4 Abort a Download Instance... 4 Display Status of Download Instances... 4 Clear Download History... 5 Configuration Examples... 5 Start New Download Instance... 5 Pause Running Download Instance... 5 Resume Paused Download Instance... 6 Start Another Download Instance Copyright 2012, Juniper Networks, Inc.

3 Introduction Juniper Networks SRX Series Services Gateways for the branch running Juniper Networks Junos operating system provide rich services like FTP, SCP, and HTTP for file download. File download processes become tedious, however, when these devices are deployed in remote locations where WAN bandwidth is low or connections are unreliable. SRX Series for the branch system software is approximately 150 MB, and downloading it through slow and unreliable WAN connections can be a tiresome process. Also, this process might hog all available bandwidth and affect performance of business critical traffic. To solve this problem, Juniper is introducing a new feature called Smart Download on its branch SRX Series platforms. This feature works very much like the Windows OS download manager, allowing the file download process to pause, resume, be scheduled at certain times, and even be allocated as a percentage of bandwidth. Smart Download is independent of the underlying file transfer protocol, and FTP and HTTP protocols are supported. Scope As of Junos OS 11.2R2, only branch SRX Series platforms support this feature, and information discussed in this document is only applicable to SRX Series for the branch platforms. Design Considerations Hardware Requirements Juniper Networks SRX100, SRX110, SRX210, SRX210E, SRX220, SRX240, SRX550, and SRX650 Services Gateways Software Requirements Junos OS 11.2R2 or greater Description and Deployment Scenario Juniper s Smart Download feature is implemented as a generic file download manager which can be used for downloading system software images and other general purpose files to SRX Series devices. Smart Download Manager is not tied to the image upgrade process and provides the following capabilities: Automatic Resume on Error: In case the download encounters errors, the system will automatically try to restart after an hour, and it will continue the download from where it stopped. If an error persists, the system will stop retrying automatically after 12 retries (12 hours). Manual Resume on Errors: In case the download encounters errors, the user will be able to resume it manually to continue from where it stopped. Automatic Resume on Reboot: When the system is rebooted, ongoing downloads will automatically resume from the place where they were before reboot. Scheduled Downloads: The user will be able to schedule a download to start at a later time. Maximum Allowed Bandwidth: A fixed amount of bandwidth can be capped for a particular file download. Full Junos OS CLI Integration: All capabilities of the download manager are available through the Junos OS CLI How to Use The Smart Download Manager will allow multiple files to be downloaded in the background. and it will monitor the status and progress of these individually. It will take automatic action whenever possible, and display status information when requested by the user. Create a New Download Instance The download process can be started by using the following CLI command in enabled mode: request system download start <URL> [delay <time in hours>] [login <login:password>] [ max-rate <expected download bandwidth>] [save-as <file name>] This command returns a unique integer download ID that can be used for future reference. All downloads will be performed in the background. The user will get back the prompt after starting a download and will be able to use the system while the download is in progress. Copyright 2012, Juniper Networks, Inc. 3

4 It is possible to start multiple download instances and have the download manager track all of them simultaneously. The parameters for this command are as follows: <URL>: URL is a mandatory parameter. It can be the FTP or HTTP of the file to be downloaded. delay: Download can be scheduled after a certain period. This parameter states number of hours after which the download can be started. Input is in hours and allowed values are login: Username and password to access file in file server. Input syntax is in username:password format. max-rate: The maximum bandwidth allowed for a particular download. Input can be in Kbps (with suffix letter k ) or Mbps (with suffix letter m ). save-as: By default, all files are downloaded to /var/tmp directory and saved with the same file name. A different name can be given with this parameter. The command shown above does some basic level error checking such as ensuring that there is enough storage space or a file with an identical name isn t already present. In case of failure, the respective error message is displayed. Pause a Running Download Instance request system download pause <download ID> This command pauses a running download instance until instructed by the user to resume processing. Only downloads in an active state can be paused; an error will occur when an attempt is made to pause a download in an inactive state. Resume Paused or Error Download request system download resume <download ID> [ max-rate <download bandwidth>] This command is used when a download is in an inactive state, either because it is stalled due to an error while downloading, or it has been paused by the user via a CLI command. Such instances can be resumed using the command shown above, and the download will start from the point where it was stopped. Once a download is restarted, the state changes to active. Also, it starts from its previous maximum allowed bandwidth by default. Optionally, a new maximum allowed bandwidth can be specified. Abort a Download Instance request system download abort <download ID> With this command, a download instance can be stopped permanently using the abort command. Only downloads in active, paused, or error state can be aborted, and once aborted, a download cannot be resumed. Any partially downloaded file will be automatically deleted to free up disk space. Information on aborted downloads can be retained in show commands. Display Status of Download Instances The system keeps track of all ongoing download information, and this data can be viewed using show commands: show system download Without any designated parameter, this command displays a summary of downloads in the following format: <ID> <State> <When download should start> <progress%> <URL> If a download-id is provided as argument, it will display a detailed report of the particular download instance specified: show system download <download ID> 4 Copyright 2012, Juniper Networks, Inc.

5 Format of detail display: Download ID : <ID> Status : <State> Progress : <Progress%> URL : <URL> Local Path : <Local path> Maximum Rate : <Max Rate> Creation Time : <Time when the start command was issued> Scheduled Time : <Time when the download should start> Start Time : <Time when the download actually started> Retry Time : <In case of error: When it will be tried again> Completion Time : <In case of completion: When it completed> Error Count : <Number of times an error was encountered> Error Message : <In case of error: Last error encountered> Clear Download History The system maintains a history of all completed, paused, error, and aborted downloads. This history can be cleared using the following command: request system download clear Limitations as of Junos OS 11.2R2 1. Smart Download is only supported on branch SRX Series platforms. 2. Only FTP and HTTP protocols are supported as underlying file transfer protocols (HTTPS is not supported). 3. FTP server should be capable of resuming partial downloads. 4. Junos Web is not supported at this time. 5. SNMP support is not available. 6. In an SRX Series chassis cluster environment, the scope of a particular download instance is limited to one node only. When a download process is started in node 0 and an SRX Series device fails to node 1, Smart Download continues to download the file on node 0, if node 0 is still able to reach the file server. Otherwise, it goes to an error state. If a new download process is started for the same file in node 1, there will be two independent copies of download processes. Configuration Examples Start New Download Instance root@srx210e-1> request system download start ftp:// /100mb_file login user:password Starting download #1 1 Active Oct 25 05:59:41 5% ftp:// /100mb_file Pause Running Download Instance root@srx210e-1> request system download pause 1 Paused download #1 1 Paused Oct 25 05:59:41 31% ftp:// /100mb_file Copyright 2012, Juniper Networks, Inc. 5

6 Resume Paused Download Instance request system download resume 1 max-rate 10k Resumed download #1 1 Active Oct 25 05:59:41 31% ftp:// /100mb_file 1 Download ID : 1 Status : Active Progress : 31% URL : ftp:// /100mb_file Local Path : /var/tmp/100mb_file Maximum Rate : 10k Creation Time : Oct 25 05:59:41 Scheduled Time : Oct 25 05:59:41 Start Time : Oct 25 06:00:54 Error Count : 0 Start Another Download Instance root@srx210e-1> request system download start ftp:// /4mb_file login user:password max-rate 1k Starting download #2 1 Active Oct 25 05:59:41 31% ftp:// /100mb_file 2 Active Oct 25 06:02:06 0% ftp:// /4mb_file Abort a Download Instance root@srx210e-1> request system download abort 1 Aborted download #1 1 Aborted Oct 25 05:59:41 - ftp:// /100mb_file 2 Active Oct 25 06:02:06 1% ftp:// /4mb_file 1 Download ID : 1 Status : Aborted Progress : - URL : ftp:// /100mb_file Local Path : /var/tmp/100mb_file Maximum Rate : 10k Creation Time : Oct 25 05:59:41 Scheduled Time : Oct 25 05:59:41 Start Time : Oct 25 06:00:54 Error Count : 0 6 Copyright 2012, Juniper Networks, Inc.

7 Summary Smart Download Manager is being introduced on SRX Series Services Gateways running Junos OS 11.2R2 or greater. It is a highly effective tool for easing the file download process, especially when slow and unreliable WAN connections are being used. It simplifies the system software image download process in remote locations. It facilitates autorecovery from download errors. It also helps with the productive utilization of slow connections for business critical applications. About Juniper Networks Juniper Networks is in the business of network innovation. From devices to data centers, from consumers to cloud providers, Juniper Networks delivers the software, silicon and systems that transform the experience and economics of networking. The company serves customers and partners worldwide. Additional information can be found at Corporate and Sales Headquarters Juniper Networks, Inc North Mathilda Avenue Sunnyvale, CA USA Phone: 888.JUNIPER ( ) or Fax: APAC and EMEA Headquarters Juniper Networks International B.V. Boeing Avenue PZ Schiphol-Rijk Amsterdam, The Netherlands Phone: Fax: To purchase Juniper Networks solutions, please contact your Juniper Networks representative at or authorized reseller. Copyright 2012 Juniper Networks, Inc. All rights reserved. Juniper Networks, the Juniper Networks logo, Junos, NetScreen, and ScreenOS are registered trademarks of Juniper Networks, Inc. in the United States and other countries. All other trademarks, service marks, registered marks, or registered service marks are the property of their respective owners. Juniper Networks assumes no responsibility for any inaccuracies in this document. Juniper Networks reserves the right to change, modify, transfer, or otherwise revise this publication without notice EN Dec 2012 Printed on recycled paper Copyright 2012, Juniper Networks, Inc. 7