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Photon OS Packages

The design of Photon OS simplifies life-cycle management and improves the security of packages. Photon reduces the burden and complexity of managing clusters of Linux machines by providing curated package repositories and by securing packages with GPG signatures.

Photon OS is available in a variety of pre-built packages in binary formats.

1 - Examining the Packages in the SPECS Directory on Github

The SPECS directory of the GitHub website for Photon OS contains all the packages that can appear in Photon OS repositories. The following is the path to the SPECS directory :

https://github.com/vmware/photon/tree/master/SPECS

To see the version of a package, in the SPECS directory, click the name of the subdirectory of the package that you want to examine, and then click the .spec filename in the subdirectory.

For example, the version of OpenJDK, which contains the openjre package that installs the Java class library and the javac Java compiler appears as follows:

%define _use_internal_dependency_generator 0
Summary:	OpenJDK 
Name:		openjdk
Version:	1.8.0.72
Release:	1%{?dist}
License:	GNU GPL
URL:		https://openjdk.java.net
Group:		Development/Tools
Vendor:		VMware, Inc.
Distribution:   Photon
AutoReqProv: 	no
Source0:	http://anduin.linuxfromscratch.org/files/BLFS/OpenJDK-%{version}/OpenJDK-%{version}-x86_64-bin.tar.xz
%define sha1 OpenJDK=0c705d7b13f4e22611d2da654209f469a6297f26
%description
The OpenJDK package installs java class library and javac java compiler. 

%package	-n openjre
Summary:	Jave runtime environment
AutoReqProv: 	no
%description	-n openjre
It contains the libraries files for Java runtime environment
#%global __requires_exclude ^libgif.*$
#%filter_from_requires ^libgif.*$...

2 - Looking at the Differences Between the Minimal and the Full Version

The minimal version of Photon OS contains around 50 packages. As it is installed, the number of packages increases to nearly 100 to fulfill dependencies. The full version of Photon OS adds several hundred packages to those in the minimal version to deliver a more fully featured operating system.

You can view a list of the packages that appear in the minimal version by examining the following file:

https://github.com/vmware/photon/blob/master/common/data/packages_minimal.json

You can view a list of the packages that appear in the full (aka “developer”) version by examining the following file:

https://github.com/vmware/photon/blob/master/common/data/packages_full.json

If the minimal or the developer version of Photon OS does not contain a package that you want, you can install it with tdnf, which appears in both the minimal and full versions of Photon OS by default. In the full version of Photon OS, you can also install packages by using yum.

One notable difference between the two versions of Photon OS pertains to OpenJDK, the package that contains not only the Java runtime environment (openjre) but also the Java compiler (javac). The OpenJDK package appears in the full but not the minimal version of Photon OS.

To add support for Java programs to the minimal version of Photon OS, install the Java packages and their dependencies by using the following command:

```console
tdnf install openjdk
Installing:
openjre 	x86_64    1.8.0.92-1.ph1    95.09 M
openjdk 	x86_64    1.8.0.92-1.ph1    37.63 M
```

NOTE: openjdk and openjre are available as openjdk8 and openjre8 in Photon OS 3.0 and later.

For more information about tdnf, see Tiny DNF for Package Management

3 - The Root Account and the 'sudo' and 'su' Commands

The Photon OS Administration Guide assumes that you are logged in to Photon OS with the root account and running commands as root.

On the minimal version, you must install sudo with tdnf if you want to use it. As an alternative to installing sudo, to run commands that require root privileges you can switch users as needed with the su command.

4 - Examining Signed Packages

Photon OS signs its packages and repositories with GPG signatures to enhance security. The GPG signature uses keyed-hash authentication method codes, typically the SHA1 algorithm and an RSA Data Security, Inc. MD5 Message Digest Algorithm, to simultaneously verify the integrity of a package. A keyed-hash message authentication code combines a cryptographic hash function with a secret cryptographic key.

In Photon OS, GPG signature verification automatically takes place when you install or update a package with the default package manager, tdnf. The default setting in the tdnf configuration file for checking the GPG is set to 1 for true:

cat /etc/tdnf/tdnf.conf
[main]
gpgcheck=1
installonly_limit=3
clean_requirements_on_remove=true
repodir=/etc/yum.repos.d
cachedir=/var/cache/tdnf

On Photon OS, you can view the key with which VMware signs packages by running the following command:

rpm -qa gpg-pubkey*

The command returns the GPG public key:

gpg-pubkey-66fd4949-4803fe57

Once you have the name of the key, you can view information about the key with the rpm -qi command, as the following abridged output demonstrates:

rpm -qi gpg-pubkey-66fd4949-4803fe57
Name        : gpg-pubkey
Version     : 66fd4949
Release     : 4803fe57
Architecture: (none)
Install Date: Thu Jun 16 11:51:39 2016
Group       : Public Keys
Size        : 0
License     : pubkey
Signature   : (none)
Source RPM  : (none)
Build Date  : Tue Apr 15 01:01:11 2008
Build Host  : localhost
Relocations : (not relocatable)
Packager    : VMware, Inc. -- Linux Packaging Key -- <linux-packages@vmware.com>
Summary     : gpg(VMware, Inc. -- Linux Packaging Key -- <linux-packages@vmware.                        com>)
Description :
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: rpm-4.11.2 (NSS-3)
mI0ESAP+VwEEAMZylR8dOijUPNn3He3GdgM/kOXEhn3uQl+sRMNJUDm1qebi2D5b ...

If you have one of the RPMs from Photon OS on another Linux system, such as Ubuntu, you can use SHA and the RSA Data Security, Inc. MD5 Message Digest Algorithm for the package to verify that it has not been tampered with:

rpm -K /home/steve/workspace/photon/stage/SRPMS/kubernetes-1.1.8-4.ph1.src.rpm
/home/steve/workspace/photon/stage/SRPMS/kubernetes-1.1.8-4.ph1.src.rpm: sha1 md5 OK

You can view the SHA1 digest and the RSA Data Security, Inc. MD5 Message Digest Algorithm by running the following command:

rpm -Kv /home/steve/workspace/photon/stage/SRPMS/kubernetes-1.1.8-4.ph1.src.rpm
/home/steve/workspace/photon/stage/SRPMS/kubernetes-1.1.8-4.ph1.src.rpm:
Header SHA1 digest: OK (89b55443d4c9f67a61ae0c1ec9bf4ece2d6aa32b)
        MD5 digest: OK (51eee659a8730e25fd2a52aff9a6c2c2)

The above examples show that the Kubernetes package has not been tampered with.

5 - Photon OS Package Repositories

The default installation of Photon OS includes four yum-compatible repositories plus the repository on the Photon OS ISO when it is available in a CD-ROM drive:

ls /etc/yum.repos.d/
photon-extras.repo
photon-iso.repo
photon-updates.repo
photon.repo 

The Photon ISO repository (photon-iso.repo) contains the installation packages for Photon OS. All the packages that Photon builds and publishes reside in the RPMs directory of the ISO when it is mounted. The RPMs directory contains metadata that lets it act as a yum repository. Mounting the ISO gives you all the packages corresponding to a Photon OS build. If, however, you built Photon OS yourself from the source code, the packages correspond only to your build, though they will typically be the latest. In contrast, the ISO that you obtain from the VMware Photon Packages web site contains only the packages that are in the ISO at the point of publication. As a result, the packages may no longer match those on in the ISO, because they are updated more frequently.

The main Photon OS repository (photon.repo) contains all the packages that are built from the ISO or from another source. This repository points to a static batch of packages and spec files at the point of a release.

The updates repository (photon-updates.repo) is irrelevant to a major release until after the release is installed. Thereafter, the updates repository holds the updated packages for that release. The repository points to updates for the installed version, such as a version of Kubernetes that supersedes the version installed during the major release.

The Photon extras repository (photon-extras.repo) holds Likewise Open, an open source authentication engine, and other VMware software that you can add to Photon OS for free. Photon OS supports but does not build the packages in the extras repository.

6 - Building a Package from a Source RPM

This section describes how to install and build a package on the full version of Photon OS from the package’s source RPM. Obtain the source RPMs that Photon OS uses from the VMWare Packages repository: packages.vmware.com/photon

Prerequisites

  • To build a package from its source RPM, or SRPM, Photon OS requires the following packages:

    • rpmbuild. This package is installed by default on the full version of Photon OS, so you should not have to install it.

    • gcc. This package is also installed by default on the full version of Photon OS, so you should not have to install it.

    • make, Cmake, automake, or another make package, depending on the package you are trying to install and build from its source RPM. Cmake is installed by default on Photon OS.

      You can install other make packages by using tdnf or yum.

  • A local unprivileged user account other than the root account. You should build RPMs as an unprivileged user. Do not build a package as root becau–building an RPM with the root account might damage your system.

  • Take a snapshot of your virtual machine before building the package if you are building a package on a virtual machine running Photon OS in VMware vSphere, VMware Workstation, or VMware Fusion.

Procedure

VMware recommends that you install and build packages from their source RPMs on the full version of Photon OS. Do not use the minimal version to work with source RPMs.

Perfrom the following steps to install and build an example package- sed from its source RPM on Photon OS with an unprivileged account.

  1. check whether rpmbuild is installed by running the following command:

    rpmbuild --version
    

    If it is not installed, install it by running the following command as root:

    tdnf install rpm-build
    
  2. Create the directories for building RPMs under your local user account home directory and not under root:

    mkdir -p ~/rpmbuild/{BUILD,RPMS,SOURCES,SPECS,SRPMS}
    
  3. Create a .rpmmacros file under your home directory and override the default location of the RPM building tree with the new one. This command overwrites an existing .rpmmacros file. Before running the following command, make sure you do not already have a .rpmmacros file. If a .rpmmacros file exists, back it up under a new name in case you want to restore it later.

    echo '%_topdir %(echo $HOME)/rpmbuild' > ~/.rpmmacros
    
  4. Place the source RPM file that you want to install and build in the /tmp directory.

  5. Install the source file, run the following command with your unprivileged user account, replacing the sed example source RPM with the name of the one that you want to install:

    rpm -i /tmp/sed-4.2.2-2.ph1.src.rpm
    

    The above command unpacks the source RPM and places its .spec file in your ~/rpmbuild/SPECS directory. In the next step, the rpmbuild tool uses the .spec file to build the RPM.

  6. Build the RPM, run the following commands with your unprivileged user account. Replace the sed.spec example file with the name of the .spec file that you want to build.

    cd ~/rpmbuild/SPECS
    rpmbuild -ba sed.spec
    

    If successful, the rpmbuild -ba command builds the RPM and generates an RPM package file in your ~/rpmbuild/RPMS/x86_64 directory. For example:

    ls RPMS/x86_64/
    sed-4.2.2-2.x86_64.rpm  sed-debuginfo-4.2.2-2.x86_64.rpm  sed-lang-4.2.2-2.x86_64.rpm
    

    The rpmbuild command also generates a new SRPM file and saves it in your ~/rpmbuild/SRPMS directory. For example:

    ls SRPMS/
    sed-4.2.2-2.src.rpm
    

    If the rpmbuild command is unsuccessful with an error that it cannot find a library, you must install the RPMs for the library that your source RPM depends on before you can successfully build your source RPM. Iterate through installing the libraries that your source RPM relies on until you can successfully build it.

  7. To install the RPM, run the following command with your unprivileged user account:

    rpm -i RPMS/x86_64/sed-4.2.2-2.x86_64.rpm
    

7 - Compiling C++ Code on the Minimal Version of Photon OS

As a minimalist Linux run-time environment, the minimal version of Photon OS lacks the packages that you need to compile the code for a C++ program. For example, without the requisite packages, trying to compile the file containing the following code with the gcc command will generate errors:

#include <stdio.h>
int main()
{
return 0;
}

The errors appear as follows:

gcc test.c
-bash: gcc: command not found
tdnf install gcc -y
gcc test.c
test.c:1:19: fatal error: stdio.h: No such file or directory
compilation terminated.

To enable the minimal version of Photon OS to preprocess, compile, assemble, and link C++ code, you must install the following packages as root with tdnf:

  • gcc
  • glibc-devel
  • binutils

To install the packages, use the following the tdnf command:

tdnf install gcc glibc-devel binutils