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Adding and Updating Packages

You use the Advanced Packaging Tool (APT) to manage additional applications (in the form of packages) and to install the latest updates.


  • apt-get

  • apt-cache

  • dpkg

Updating the Package Cache

To work properly, APT relies on a local cache of the available packages. You must populate the cache initially, and then periodically update it with apt-get update:

cumulus@switch:~$ sudo apt-get update
Get:1 CumulusLinux-3 InRelease [7,624 B]
Get:2 CumulusLinux-3-security-updates InRelease [7,555 B]
Get:3 CumulusLinux-3-updates InRelease [7,660 B]
Get:4 CumulusLinux-3/cumulus Sources [20 B]
Get:5 CumulusLinux-3/upstream Sources [20 B]
Get:6 CumulusLinux-3/cumulus amd64 Packages [38.4 kB]
Get:7 CumulusLinux-3/upstream amd64 Packages [445 kB]
Get:8 CumulusLinux-3-security-updates/cumulus Sources [20 B]
Get:9 CumulusLinux-3-security-updates/upstream Sources [11.8 kB]
Get:10 CumulusLinux-3-security-updates/cumulus amd64 Packages [20 B]
Get:11 CumulusLinux-3-security-updates/upstream amd64 Packages [8,941 B]
Get:12 CumulusLinux-3-updates/cumulus Sources [20 B]
Get:13 CumulusLinux-3-updates/upstream Sources [776 B]
Get:14 CumulusLinux-3-updates/cumulus amd64 Packages [38.4 kB]
Get:15 CumulusLinux-3-updates/upstream amd64 Packages [444 kB]
Ign CumulusLinux-3/cumulus Translation-en_US
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Ign CumulusLinux-3/upstream Translation-en_US
Ign CumulusLinux-3/upstream Translation-en
Ign CumulusLinux-3-security-updates/cumulus Translation-en_US
Ign CumulusLinux-3-security-updates/cumulus Translation-en
Ign CumulusLinux-3-security-updates/upstream Translation-en_US
Ign CumulusLinux-3-security-updates/upstream Translation-en
Ign CumulusLinux-3-updates/cumulus Translation-en_US
Ign CumulusLinux-3-updates/cumulus Translation-en
Ign CumulusLinux-3-updates/upstream Translation-en_US
Ign CumulusLinux-3-updates/upstream Translation-en
Fetched 1,011 kB in 1s (797 kB/s)
Reading package lists... Done

Listing Available Packages

Once the cache is populated, use apt-cache to search the cache to find the packages you are interested in or to get information about an available package. Here are examples of the search and show sub-commands:

cumulus@switch:~$ apt-cache search tcp
socat - multipurpose relay for bidirectional data transfer
quagga-doc - documentation files for quagga
fakeroot - tool for simulating superuser privileges
quagga - BGP/OSPF/RIP routing daemon
tcpdump - command-line network traffic analyzer
openssh-server - secure shell (SSH) server, for secure access from remote machines
openssh-sftp-server - secure shell (SSH) sftp server module, for SFTP access from remote machines
python-dpkt - Python packet creation / parsing module
libfakeroot - tool for simulating superuser privileges - shared libraries
openssh-client - secure shell (SSH) client, for secure access to remote machines
rsyslog - reliable system and kernel logging daemon
libwrap0 - Wietse Venema's TCP wrappers library
netbase - Basic TCP/IP networking system

cumulus@switch:~$ apt-cache show tcpdump
Package: tcpdump
Status: install ok installed
Priority: optional
Section: net
Installed-Size: 1092
Maintainer: Romain Francoise <>
Architecture: amd64
Multi-Arch: foreign
Version: 4.6.2-5+deb8u1
Depends: libc6 (>= 2.14), libpcap0.8 (>= 1.5.1), libssl1.0.0 (>= 1.0.0)
Description: command-line network traffic analyzer
 This program allows you to dump the traffic on a network. tcpdump
 is able to examine IPv4, ICMPv4, IPv6, ICMPv6, UDP, TCP, SNMP, AFS
 BGP, RIP, PIM, DVMRP, IGMP, SMB, OSPF, NFS and many other packet
 It can be used to print out the headers of packets on a network
 interface, filter packets that match a certain expression. You can
 use this tool to track down network problems, to detect attacks
 or to monitor network activities.
Description-md5: f01841bfda357d116d7ff7b7a47e8782

The search commands look for the search terms not only in the package name but in other parts of the package information. Consequently, it will match on more packages than you would expect.

Adding a Package

In order to add a new package, first ensure the package is not already installed in the system:

cumulus@switch:~$ dpkg -l | grep {name of package}

If the package is installed already, ensure it’s the version you need. If it’s an older version, then update the package from the Cumulus Linux repository:

cumulus@switch:~$ sudo apt-get update

If the package is not already on the system, add it by running apt-get install. This retrieves the package from the Cumulus Linux repository and installs it on your system together with any other packages that this package might depend on.

For example, the following adds the package tcpreplay to the system:

cumulus@switch:~$ sudo apt-get install tcpreplay
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
0 upgraded, 1 newly installed, 0 to remove and 1 not upgraded.
Need to get 436 kB of archives.
After this operation, 1008 kB of additional disk space will be used.
Get:1 CumulusLinux-1.5/main tcpreplay amd64 4.6.2-5+deb8u1 [436 kB]
Fetched 436 kB in 0s (1501 kB/s)
Selecting previously unselected package tcpreplay.
(Reading database ... 15930 files and directories currently installed.)
Unpacking tcpreplay (from .../tcpreplay_4.6.2-5+deb8u1_amd64.deb) ...
Processing triggers for man-db ...
Setting up tcpreplay (4.6.2-5+deb8u1) ...

Listing Installed Packages

The APT cache contains information about all the packages available on the repository. To see which packages are actually installed on your system, use dpkg. The following example lists all the packages on the system that have “tcp” in their package names:

cumulus@switch:~$ dpkg -l \*tcp\*
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                          Version             Architecture        Description
un  tcpd                          <none>              <none>              (no description available)
ii  tcpdump                       4.6.2-5+deb8u1      amd64               command-line network traffic analyzer

Upgrading to Newer Versions of Installed Packages

Upgrading a Single Package

A single package can be upgraded by simply installing that package again with apt-get install. You should perform an update first so that the APT cache is populated with the latest information about the packages.

To see if a package needs to be upgraded, use apt-cache show <pkgname> to show the latest version number of the package. Use dpkg -l <pkgname> to show the version number of the installed package.

Upgrading All Packages

You can update all packages on the system by running apt-get update, then apt-get upgrade. This upgrades all installed versions with their latest versions but will not install any new packages.

Adding Packages from Another Repository

As shipped, Cumulus Linux searches the Cumulus Linux repository for available packages. You can add additional repositories to search by adding them to the list of sources that apt-get consults. See man sources.list for more information.

For several packages, Cumulus Networks has added features or made bug fixes and these packages must not be replaced with versions from other repositories. Cumulus Linux has been configured to ensure that the packages from the Cumulus Linux repository are always preferred over packages from other repositories.

If you want to install packages that are not in the Cumulus Linux repository, the procedure is the same as above with one additional step.

Packages not part of the Cumulus Linux Repository have generally not been tested, and may not be supported by Cumulus Linux support.

Installing packages outside of the Cumulus Linux repository requires the use of apt-get, but, depending on the package, easy-install and other commands can also be used.

To install a new package, please complete the following steps:

  1. First, ensure package is not already installed in the system. Use the dpkg command:

    cumulus@switch:~$ dpkg -l | grep {name of package}
  2. If the package is installed already, ensure it’s the version you need. If it’s an older version, then update the package from the Cumulus Linux repository:

    cumulus@switch:~$ sudo apt-get update
    cumulus@switch:~$ sudo apt-get install {name of package}
  3. If the package is not on the system, then most likely the package source location is also not in the /etc/apt/sources.list file. If the source for the new package is not in sources.list, please edit and add the appropriate source to the file. For example, add the following if you wanted a package from the Debian repository that is not in the Cumulus Linux repository:

    deb jessie main
    deb jessie/updates main

    Otherwise, the repository may be listed in /etc/apt/sources.list but is commented out, as can be the case with the early-access repository:

    #deb CumulusLinux-3-early-access cumulus

    To uncomment the repository, remove the # at the start of the line, then save the file:

    deb CumulusLinux-3-early-access cumulus
  4. Run apt-get update then install the package:

    cumulus@switch:~$ sudo apt-get update
    cumulus@switch:~$ sudo apt-get install {name of package}

Configuration Files

  • /etc/apt/apt.conf

  • /etc/apt/preferences

  • /etc/apt/sources.list

Useful Links