The Atomic Series. Part 1 - Introduction to Atomic Host

Welcome to the Atomic Series! In this new series of articles I will discuss the different part of the Project Atomic ecosystem starting with the Atomic Host in this first part. I sincerely hope you like it found it helpful. The planned posts, for now are:

Part 1 - Introduction to Atomic Host Part 2 - Atomic Registry Part 3 - Atomic clusters

In the future I am planning to write more posts around Atomic but without numbering.

What is Project Atomic?

Project Atomic is the name of the community, sponsored by Red Hat, that encompass a set of Open Source projects geared towards creating of a new family of operating systems and infrastructure to run container-based workloads.

The basic building block of the project is the Atomic Host, a lightweight container operating system, however the project also serves as the umbrella of projects like rpm-ostree, Atomic Registry, Atomic App or Cockpit which are also components of Openshift Origin, the upstream of Red Hat Openshift Container Platform. Project Atomic includes the upstream work on Docker and Kubernetes communities.

What is Atomic Host

Atomic Host is a lightweight container optimized operating system designed to be immutable, currently available as Fedora and CentOS flavors, is also the upstream of Red Hat Enterprise linux Atomic Host. It is very important to understand that Atomic Host is not a new Linux distribution but it is built on the foundation of Fedora, CentOS and Red Hat Enterprise Linux.

It differs from traditional operating systems, which by the way can also run containers, in that it is optimized to run and managing containers. Every application is run and managed as a container in Atomic Host.

Besides of the container optimized host it provides tools like rpm-ostree , Docker , Kubernetes , Cockpit and the Atomic command line tools. Currently the only components that come installed in Atomic, besides of the Fedora, CentOS or RHEL base images, are the Atomic command line, Docker and Kubernetes; however there are plans to implement Kubernetes as containers in the future as well.

rpm-ostree

Based on OSTree , the first thing you have to know about rpm-ostree is that it is not a package management system like yum , dnf or apt . Instead rpm-ostree is an open source tool to manage bootable, immutable, versioned filesystem trees. The main idea behind rpm-ostree is to use a client-server architecture to keep Linux hosts updated and in sync with the latest packages in a reliable manner.

Check current status [fedora@atomic-01 ~]$ sudo rpm-ostree status TIMESTAMP (UTC) VERSION ID OSNAME REFSPEC * 2016-06-15 09:57:04 24.39 2c7d41e8a6 fedora-atomic fedora-atomic:fedora-atomic/24/x86_64/docker-host [fedora@atomic-01 ~]$ [fedora@fed-atomic-01 ~]$ sudo rpm-ostree status -p ============================================================ * DEFAULT ON BOOT ---------------------------------------- version 24.39 timestamp 2016-06-15 09:57:04 id 2c7d41e8a67931fe21bc92100c59cff8a94c2df5a0e6a1b75957bda141601481.0 osname fedora-atomic refspec fedora-atomic:fedora-atomic/24/x86_64/docker-host ============================================================ [fedora@fed-atomic-01 ~]$ Upgrade the system

The upgrade option allows you also to preview the changes, display the current version, etc.

[fedora@fed-atomic-01 ~]$ sudo rpm-ostree upgrade --help Usage: rpm-ostree upgrade [OPTION...] - Perform a system upgrade Help Options: -h, --help Show help options Application Options: --os=OSNAME Operate on provided OSNAME -r, --reboot Initiate a reboot after an upgrade is prepared --allow-downgrade Permit deployment of chronologically older trees --preview Just preview package differences --check Just check if an upgrade is available --sysroot=SYSROOT Use system root SYSROOT (default: /) --peer Force a peer-to-peer connection instead of using the system message bus --version Print version information and exit [fedora@fed-atomic-01 ~]$ [fedora@fed-atomic-01 ~]$ sudo rpm-ostree upgrade --version rpm-ostree 2015.11 +compose [fedora@fed-atomic-01 ~]$

Performing the upgrade is a simple rpm-ostree upgrade .

[fedora@fed-atomic-01 ~]$ sudo rpm-ostree upgrade Updating from: fedora-atomic:fedora-atomic/24/x86_64/docker-host 2061 metadata, 9718 content objects fetched; 354168 KiB transferred in 551 seconds Copying /etc changes: 20 modified, 0 removed, 46 added Transaction complete; bootconfig swap: yes deployment count change: 1 [fedora@fed-atomic-01 ~]$

After the upgrade reboot the host and verify the new tree is in use.

[fedora@fed-atomic-01 ~]$ sudo rpm-ostree status State: idle Deployments: ● fedora-atomic:fedora-atomic/24/x86_64/docker-host Version: 24.81 (2016-11-14 20:46:13) Commit: 49dd9520a7c537ced9c846c2e2f47643b5f52a22768d944b6d8c1108da38f39e OSName: fedora-atomic fedora-atomic:fedora-atomic/24/x86_64/docker-host Version: 24.39 (2016-06-15 09:57:04) Commit: 2c7d41e8a67931fe21bc92100c59cff8a94c2df5a0e6a1b75957bda141601481 OSName: fedora-atomic [fedora@fed-atomic-01 ~]$ Rollback an upgrade [fedora@fed-atomic-01 ~]$ sudo rpm-ostree rollback Moving '2c7d41e8a67931fe21bc92100c59cff8a94c2df5a0e6a1b75957bda141601481.0' to be first deployment Transaction complete; bootconfig swap: yes deployment count change: 0 Changed: NetworkManager 1:1.2.4-3.fc24 -> 1:1.2.2-1.fc24 NetworkManager-libnm 1:1.2.4-3.fc24 -> 1:1.2.2-1.fc24 atomic 1.13.1-3.git5dfcaa9.fc24 -> 1.8-5.gitcc5997a.fc24 audit 2.6.7-1.fc24 -> 2.5.2-1.fc24 audit-libs 2.6.7-1.fc24 -> 2.5.2-1.fc24 audit-libs-python 2.6.7-1.fc24 -> 2.5.2-1.fc24 audit-libs-python3 2.6.7-1.fc24 -> 2.5.2-1.fc24 bash 4.3.42-7.fc24 -> 4.3.42-5.fc24 bash-completion 1:2.4-1.fc24 -> 1:2.3-1.fc24 bind99-libs 9.9.9-2.P3.fc24 -> 9.9.9-1.P1.fc24 bind99-license 9.9.9-2.P3.fc24 -> 9.9.9-1.P1.fc24 boost-iostreams 1.60.0-7.fc24 -> 1.60.0-5.fc24 boost-program-options 1.60.0-7.fc24 -> 1.60.0-5.fc24 boost-random 1.60.0-7.fc24 -> 1.60.0-5.fc24 boost-regex 1.60.0-7.fc24 -> 1.60.0-5.fc24 boost-system 1.60.0-7.fc24 -> 1.60.0-5.fc24 boost-thread 1.60.0-7.fc24 -> 1.60.0-5.fc24 ca-certificates 2016.2.10-1.0.fc24 -> 2016.2.7-1.0.fc24 ceph-common 1:10.2.2-2.fc24 -> 1:10.2.0-2.fc24 checkpolicy 2.5-6.fc24 -> 2.5-2.fc24 chkconfig 1.8-1.fc24 -> 1.7-2.fc24 cockpit-bridge 0.117-1.fc24 -> 0.103-1.fc24 cockpit-docker 0.117-1.fc24 -> 0.103-1.fc24 cockpit-networkmanager 0.117-1.fc24 -> 0.103-1.fc24 cockpit-ostree 0.117-1.fc24 -> 0.103-1.fc24 cockpit-shell 0.117-1.fc24 -> 0.103-1.fc24 coreutils 8.25-7.fc24 -> 8.25-5.fc24 coreutils-common 8.25-7.fc24 -> 8.25-5.fc24 cronie 1.5.1-2.fc24 -> 1.5.0-4.fc24 cronie-anacron 1.5.1-2.fc24 -> 1.5.0-4.fc24 cryptsetup 1.7.2-1.fc24 -> 1.7.1-1.fc24 cryptsetup-libs 1.7.2-1.fc24 -> 1.7.1-1.fc24 curl 7.47.1-9.fc24 -> 7.47.1-4.fc24 dbus 1:1.11.6-1.fc24 -> 1:1.11.2-1.fc24 dbus-glib 0.108-1.fc24 -> 0.106-1.fc24 dbus-libs 1:1.11.6-1.fc24 -> 1:1.11.2-1.fc24 device-mapper 1.02.122-2.fc24 -> 1.02.122-1.fc24 device-mapper-event 1.02.122-2.fc24 -> 1.02.122-1.fc24 device-mapper-event-libs 1.02.122-2.fc24 -> 1.02.122-1.fc24 device-mapper-libs 1.02.122-2.fc24 -> 1.02.122-1.fc24 device-mapper-persistent-data 0.6.3-1.fc24 -> 0.6.2-0.1.rc6.fc24 dhcp-client 12:4.3.4-3.fc24 -> 12:4.3.4-2.fc24 dhcp-common 12:4.3.4-3.fc24 -> 12:4.3.4-2.fc24 dhcp-libs 12:4.3.4-3.fc24 -> 12:4.3.4-2.fc24 dnsmasq 2.76-1.fc24 -> 2.75-4.fc24 docker 2:1.10.3-54.gite03ddb8.fc24 -> 2:1.10.3-9.git667d6d1.fc24 docker-v1.10-migrator 2:1.10.3-54.gite03ddb8.fc24 -> 2:1.10.3-9.git667d6d1.fc24 dracut 044-21.fc24 -> 044-18.git20160108.fc24 dracut-config-generic 044-21.fc24 -> 044-18.git20160108.fc24 dracut-live 044-21.fc24 -> 044-18.git20160108.fc24 dracut-network 044-21.fc24 -> 044-18.git20160108.fc24 efibootmgr 14-3.fc24 -> 0.12-3.fc24 efivar-libs 30-4.fc24 -> 0.23-1.fc24 elfutils-default-yama-scope 0.167-1.fc24 -> 0.166-2.fc24 elfutils-libelf 0.167-1.fc24 -> 0.166-2.fc24 elfutils-libs 0.167-1.fc24 -> 0.166-2.fc24 emacs-filesystem 1:25.1-2.fc24 -> 1:25.0.94-1.fc24 etcd 2.3.3-1.fc24 -> 2.2.5-5.fc24 expat 2.1.1-2.fc24 -> 2.1.1-1.fc24 fedora-release 24-2 -> 24-1 fedora-repos 24-3 -> 24-1 findutils 1:4.6.0-7.fc24 -> 1:4.6.0-3.fc24 flannel 0.5.5-6.fc24 -> 0.5.5-5.fc24 fuse-libs 2.9.7-1.fc24 -> 2.9.4-4.fc24 gawk 4.1.3-8.fc24 -> 4.1.3-3.fc24 gettext 0.19.8.1-2.fc24 -> 0.19.7-4.fc24 gettext-libs 0.19.8.1-2.fc24 -> 0.19.7-4.fc24 glib2 2.48.2-1.fc24 -> 2.48.1-1.fc24 glibc 2.23.1-11.fc24 -> 2.23.1-7.fc24 glibc-all-langpacks 2.23.1-11.fc24 -> 2.23.1-7.fc24 glibc-common 2.23.1-11.fc24 -> 2.23.1-7.fc24 glusterfs 3.8.5-1.fc24 -> 3.8.0-0.2.rc2.fc24 glusterfs-client-xlators 3.8.5-1.fc24 -> 3.8.0-0.2.rc2.fc24 glusterfs-fuse 3.8.5-1.fc24 -> 3.8.0-0.2.rc2.fc24 glusterfs-libs 3.8.5-1.fc24 -> 3.8.0-0.2.rc2.fc24 gmp 1:6.1.1-1.fc24 -> 1:6.1.0-2.fc24 gnupg2 2.1.13-2.fc24 -> 2.1.11-3.fc24 gnutls 3.4.16-1.fc24 -> 3.4.12-1.fc24 gpgme 1.6.0-3.fc24 -> 1.4.3-7.fc24 gssproxy 0.5.1-3.fc24 -> 0.5.0-4.fc24 guile 5:2.0.13-1.fc24 -> 5:2.0.11-9.fc24 info 6.1-3.fc24 -> 6.1-2.fc24 ipcalc 0.1.8-1.fc24 -> 0.1.6-2.fc24 iputils 20160308-3.fc24 -> 20160308-2.fc24 json-glib 1.2.2-1.fc24 -> 1.2.0-1.fc24 kernel 4.8.6-201.fc24 -> 4.5.5-300.fc24 kernel-core 4.8.6-201.fc24 -> 4.5.5-300.fc24 kernel-modules 4.8.6-201.fc24 -> 4.5.5-300.fc24 krb5-libs 1.14.4-4.fc24 -> 1.14.1-6.fc24 kubernetes 1.2.0-0.26.git4a3f9c5.fc24 -> 1.2.0-0.20.git4a3f9c5.fc24 kubernetes-client 1.2.0-0.26.git4a3f9c5.fc24 -> 1.2.0-0.20.git4a3f9c5.fc24 kubernetes-master 1.2.0-0.26.git4a3f9c5.fc24 -> 1.2.0-0.20.git4a3f9c5.fc24 kubernetes-node 1.2.0-0.26.git4a3f9c5.fc24 -> 1.2.0-0.20.git4a3f9c5.fc24 libarchive 3.2.2-1.fc24 -> 3.1.2-17.fc24 libassuan 2.4.3-1.fc24 -> 2.4.2-2.fc24 libbasicobjects 0.1.1-29.fc24 -> 0.1.1-28.fc24 libblkid 2.28.2-1.fc24 -> 2.28-2.fc24 libcap-ng 0.7.8-1.fc24 -> 0.7.7-4.fc24 libcephfs1 1:10.2.2-2.fc24 -> 1:10.2.0-2.fc24 libcollection 0.7.0-29.fc24 -> 0.7.0-28.fc24 libcurl 7.47.1-9.fc24 -> 7.47.1-4.fc24 libfdisk 2.28.2-1.fc24 -> 2.28-2.fc24 libgcc 6.2.1-2.fc24 -> 6.1.1-2.fc24 libgcrypt 1.6.6-1.fc24 -> 1.6.4-2.fc24 libgomp 6.2.1-2.fc24 -> 6.1.1-2.fc24 libgpg-error 1.24-1.fc24 -> 1.21-2.fc24 libicu 56.1-5.fc24 -> 56.1-4.fc24 libidn 1.33-1.fc24 -> 1.32-2.fc24 libini_config 1.3.0-29.fc24 -> 1.2.0-28.fc24 libksba 1.3.5-1.fc24 -> 1.3.4-1.fc24 libmnl 1.0.4-1.fc24 -> 1.0.3-11.fc24 libmount 2.28.2-1.fc24 -> 2.28-2.fc24 libnfsidmap 0.26-6.rc4.fc24 -> 0.26-4.2.fc24 libnl3 3.2.28-3.fc24 -> 3.2.27-3.fc24 libpath_utils 0.2.1-29.fc24 -> 0.2.1-28.fc24 libpng 2:1.6.26-1.fc24 -> 2:1.6.21-2.fc24 libpsl 0.13.0-3.fc24 -> 0.13.0-1.fc24 librados2 1:10.2.2-2.fc24 -> 1:10.2.0-2.fc24 libradosstriper1 1:10.2.2-2.fc24 -> 1:10.2.0-2.fc24 librbd1 1:10.2.2-2.fc24 -> 1:10.2.0-2.fc24 libref_array 0.1.5-29.fc24 -> 0.1.5-28.fc24 librgw2 1:10.2.2-2.fc24 -> 1:10.2.0-2.fc24 libselinux 2.5-9.fc24 -> 2.5-3.fc24 libselinux-python 2.5-9.fc24 -> 2.5-3.fc24 libselinux-python3 2.5-9.fc24 -> 2.5-3.fc24 libselinux-utils 2.5-9.fc24 -> 2.5-3.fc24 libsemanage 2.5-5.fc24 -> 2.5-2.fc24 libsemanage-python 2.5-5.fc24 -> 2.5-2.fc24 libsemanage-python3 2.5-5.fc24 -> 2.5-2.fc24 libsepol 2.5-8.fc24 -> 2.5-3.fc24 libsmartcols 2.28.2-1.fc24 -> 2.28-2.fc24 libsolv 0.6.24-1.fc24 -> 0.6.20-3.fc24 libsss_idmap 1.14.2-1.fc24 -> 1.13.4-3.fc24 libsss_nss_idmap 1.14.2-1.fc24 -> 1.13.4-3.fc24 libsss_sudo 1.14.2-1.fc24 -> 1.13.4-3.fc24 libstdc++ 6.2.1-2.fc24 -> 6.1.1-2.fc24 libtasn1 4.9-1.fc24 -> 4.8-1.fc24 libtool-ltdl 2.4.6-12.fc24 -> 2.4.6-11.fc24 libuuid 2.28.2-1.fc24 -> 2.28-2.fc24 libxkbcommon 0.6.1-1.fc24 -> 0.5.0-4.fc24 linux-firmware 20160923-68.git42ad5367.fc24 -> 20160526-65.git80d463be.fc24 lua 5.3.3-2.fc24 -> 5.3.2-3.fc24 lvm2 2.02.150-2.fc24 -> 2.02.150-1.fc24 lvm2-libs 2.02.150-2.fc24 -> 2.02.150-1.fc24 mokutil 1:0.3.0-2.fc24 -> 1:0.2.0-4.fc24 ncurses 6.0-6.20160709.fc24 -> 6.0-5.20160116.fc24 ncurses-base 6.0-6.20160709.fc24 -> 6.0-5.20160116.fc24 ncurses-libs 6.0-6.20160709.fc24 -> 6.0-5.20160116.fc24 nettle 3.2-3.fc24 -> 3.2-2.fc24 nfs-utils 1:1.3.4-1.rc2.fc24 -> 1:1.3.3-8.rc5.fc24 nspr 4.13.1-1.fc24 -> 4.12.0-1.fc24 nss 3.27.0-1.2.fc24 -> 3.23.0-1.2.fc24 nss-softokn 3.27.0-1.0.fc24 -> 3.23.0-1.0.fc24 nss-softokn-freebl 3.27.0-1.0.fc24 -> 3.23.0-1.0.fc24 nss-sysinit 3.27.0-1.2.fc24 -> 3.23.0-1.2.fc24 nss-tools 3.27.0-1.2.fc24 -> 3.23.0-1.2.fc24 nss-util 3.27.0-1.0.fc24 -> 3.23.0-1.0.fc24 oci-register-machine 0-2.4.git352a2a2.fc24 -> 0-1.1.git7d4ce65.fc24 openssh 7.2p2-13.fc24 -> 7.2p2-6.fc24 openssh-clients 7.2p2-13.fc24 -> 7.2p2-6.fc24 openssh-server 7.2p2-13.fc24 -> 7.2p2-6.fc24 openssl 1:1.0.2j-1.fc24 -> 1:1.0.2h-1.fc24 openssl-libs 1:1.0.2j-1.fc24 -> 1:1.0.2h-1.fc24 ostree 2016.12-1.fc24 -> 2016.5-3.fc24 ostree-grub2 2016.12-1.fc24 -> 2016.5-3.fc24 pcre 8.39-6.fc24 -> 8.38-11.fc24 policycoreutils 2.5-13.fc24 -> 2.5-5.fc24 policycoreutils-python 2.5-13.fc24 -> 2.5-5.fc24 policycoreutils-python-utils 2.5-13.fc24 -> 2.5-5.fc24 policycoreutils-python3 2.5-13.fc24 -> 2.5-5.fc24 python 2.7.12-6.fc24 -> 2.7.11-4.fc24 python-cephfs 1:10.2.2-2.fc24 -> 1:10.2.0-2.fc24 python-libs 2.7.12-6.fc24 -> 2.7.11-4.fc24 python-rados 1:10.2.2-2.fc24 -> 1:10.2.0-2.fc24 python-rbd 1:10.2.2-2.fc24 -> 1:10.2.0-2.fc24 python2-pysocks 1.5.6-4.fc24 -> 1.5.6-3.fc24 python3 3.5.2-3.fc24 -> 3.5.1-7.fc24 python3-jinja2 2.8-7.fc24 -> 2.8-5.fc24 python3-libs 3.5.2-3.fc24 -> 3.5.1-7.fc24 python3-pyserial 3.1.1-1.fc24 -> 2.7-5.fc24 python3-pysocks 1.5.6-4.fc24 -> 1.5.6-3.fc24 python3-requests 2.10.0-2.fc24 -> 2.10.0-1.fc24 python3-sssdconfig 1.14.2-1.fc24 -> 1.13.4-3.fc24 python3-urllib3 1.15.1-3.fc24 -> 1.15.1-1.fc24 rpcbind 0.2.3-11.rc1.fc24 -> 0.2.3-10.rc1.fc24 rpm-ostree 2016.11-1.fc24 -> 2015.11-2.fc24 runc 1:0.1.1-3.git57b9972.fc24 -> 1:0.0.9-0.3.git94dc520.fc24 screen 4.4.0-4.fc24 -> 4.3.1-4.fc24 selinux-policy 3.13.1-191.20.fc24 -> 3.13.1-190.fc24 selinux-policy-targeted 3.13.1-191.20.fc24 -> 3.13.1-190.fc24 skopeo 0.1.14-5.git550a480.fc24 -> 0.1.11-1.fc24 sqlite 3.13.0-1.fc24 -> 3.11.0-3.fc24 sqlite-libs 3.13.0-1.fc24 -> 3.11.0-3.fc24 sssd-client 1.14.2-1.fc24 -> 1.13.4-3.fc24 strace 4.14-1.fc24 -> 4.11.0.163.9720-2.fc24 sudo 1.8.18p1-1.fc24 -> 1.8.16-3.fc24 system-python-libs 3.5.2-3.fc24 -> 3.5.1-7.fc24 systemd 229-16.fc24 -> 229-8.fc24 systemd-container 229-16.fc24 -> 229-8.fc24 systemd-libs 229-16.fc24 -> 229-8.fc24 systemd-udev 229-16.fc24 -> 229-8.fc24 tzdata 2016i-1.fc24 -> 2016d-1.fc24 util-linux 2.28.2-1.fc24 -> 2.28-2.fc24 vim-minimal 2:7.4.1868-1.fc24 -> 2:7.4.1718-1.fc24 xfsprogs 4.5.0-2.fc24 -> 4.5.0-1.fc24 Removed: bubblewrap-0.1.3-2.fc24.x86_64 container-selinux-2:1.10.3-54.gite03ddb8.fc24.x86_64 docker-common-2:1.10.3-54.gite03ddb8.fc24.x86_64 fedora-release-atomichost-24-2.noarch fuse-2.9.7-1.fc24.x86_64 gobject-introspection-1.48.0-1.fc24.x86_64 libev-4.20-2.fc24.x86_64 libreport-filesystem-2.7.2-1.fc24.x86_64 libsigsegv-2.10-10.fc24.x86_64 libverto-libev-0.2.6-6.fc24.x86_64 mdadm-3.4-2.fc24.x86_64 mpfr-3.1.5-1.fc24.x86_64 nss-pem-1.0.2-2.fc24.x86_64 python2-requests-2.10.0-2.fc24.noarch python2-urllib3-1.15.1-3.fc24.noarch python3-dateutil-1:2.5.2-2.fc24.noarch python3-gobject-base-3.20.1-1.fc24.x86_64 skopeo-containers-0.1.14-5.git550a480.fc24.x86_64 Added: GeoIP-1.6.9-2.fc24.x86_64 GeoIP-GeoLite-data-2016.05-1.fc24.noarch docker-selinux-2:1.10.3-9.git667d6d1.fc24.x86_64 gnupg2-smime-2.1.11-3.fc24.x86_64 hawkey-0.6.3-2.fc24.x86_64 libhif-0.2.2-4.fc24.x86_64 libsecret-0.18.5-1.fc24.x86_64 libtalloc-2.1.6-1.fc24.x86_64 libtevent-0.9.28-1.fc24.x86_64 libusb-1:0.1.5-7.fc24.x86_64 libusbx-1.0.21-0.1.git448584a.fc24.x86_64 libverto-tevent-0.2.6-6.fc24.x86_64 pinentry-0.9.7-2.fc24.x86_64 python-requests-2.10.0-1.fc24.noarch python-urllib3-1.15.1-1.fc24.noarch Run "systemctl reboot" to start a reboot [fedora@fed-atomic-01 ~]$

Reboot the host and verify it is using the previous tree version.

[fedora@fed-atomic-01 ~]$ sudo rpm-ostree status TIMESTAMP (UTC) VERSION ID OSNAME REFSPEC * 2016-06-15 09:57:04 24.39 2c7d41e8a6 fedora-atomic fedora-atomic:fedora-atomic/24/x86_64/docker-host 2016-11-14 20:46:13 24.81 49dd9520a7 fedora-atomic fedora-atomic:fedora-atomic/24/x86_64/docker-host [fedora@fed-atomic-01 ~]$ sudo rpm-ostree status -p ============================================================ * DEFAULT ON BOOT ---------------------------------------- version 24.39 timestamp 2016-06-15 09:57:04 id 2c7d41e8a67931fe21bc92100c59cff8a94c2df5a0e6a1b75957bda141601481.0 osname fedora-atomic refspec fedora-atomic:fedora-atomic/24/x86_64/docker-host ============================================================ NON-DEFAULT ROLLBACK TARGET ---------------------------------------- version 24.81 timestamp 2016-11-14 20:46:13 id 49dd9520a7c537ced9c846c2e2f47643b5f52a22768d944b6d8c1108da38f39e.0 osname fedora-atomic refspec fedora-atomic:fedora-atomic/24/x86_64/docker-host ============================================================ [fedora@fed-atomic-01 ~]$ Atomic command line

Atomic includes a new cli called atomic , provides a coherent entry point to manage Atomic Hosts. Under the hood atomic command is a wrapper that allows an administrator to perform container and host maintenance operations using a unified interface.

usage: atomic [-h] [-v] [--debug] [-y] {containers,diff,help,images,host,info,install,mount,pull,push,upload,run,scan,sign,stop,storage,migrate,top,trust,uninstall,unmount,umount,update,verify,version} ... Atomic Management Tool positional arguments: {containers,diff,help,images,host,info,install,mount,pull,push,upload,run,scan,sign,stop,storage,migrate,top,trust,uninstall,unmount,umount,update,verify,version} commands containers operate on containers diff Show differences between two container images, file diff or RPMS. images operate on images host execute Atomic host commands install execute container image install method mount mount container image to a specified directory pull pull latest image from a repository push (upload) push latest image to repository run execute container image run method scan scan an image or container for CVEs sign Sign an image stop execute container image stop method storage (migrate) manage container storage top Show top-like stats about processes running in containers trust Manage system container trust policy uninstall execute container image uninstall method unmount (umount) unmount container image update pull latest container image from repository optional arguments: -h, --help show this help message and exit -v, --version show atomic version and exit --debug show debug messages -y, --assumeyes automatically answer yes for all questions [fedora@fed-atomic-01 ~]$ Container operations

atomic can be used for container management operations in several ways, at first sight it looks like a sot of wrapper for docker to perform many operations like run, stop, list images, etc, however for an atomic run operation it will grab the run LABEL and execute it with no need for the user to pass any parameters. atomic implements the command install which instead of jst importing the container image in the host with its corresponding Kubernetes configuration or Systemd unit file.

[fedora@fed-atomic-01 ~]$ sudo atomic run alpine sh Trying docker.io/library/alpine:latest Uploading blob sha256:baa5d63471ead618ff91ddfacf1e2c81bf0612bfeb1daf00eb0843a41fbfade3 0 B / 1.25 KB [---------------------------------------------------------------] Uploading blob sha256:3690ec4760f95690944da86dc4496148a63d85c9e3100669a318110092f6862f 0 B / 2.21 MB [---------------------------------------------------------------] Uploading manifest to image destination Storing signatures 2.21 MB / 2.21 MB [===========================================================]docker run -t -i --name alpine alpine sh / #

atomic also allows to manage the installed Docker images.

[fedora@fed-atomic-01 ~]$ sudo atomic images list REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE TYPE > docker.io/nginx latest 05a60462f8ba 2016-11-08 23:41 181.44 MB Docker > docker.io/cockpit/ws latest 0c8d8b92a26e 2016-11-02 19:14 532.96 MB Docker > docker.io/alpine latest baa5d63471ea 2016-10-18 22:31 4.8 MB Docker [fedora@fed-atomic-01 ~]$ [fedora@fed-atomic-01 ~]$ sudo atomic images info 0c8d8b92a26e Image Name: 0c8d8b92a26e RUN: /usr/bin/docker run -d --privileged --pid=host -v /:/host IMAGE /container/atomic-run --local-ssh UNINSTALL: /usr/bin/docker run -ti --rm --privileged -v /:/host IMAGE /container/atomic-uninstall INSTALL: /usr/bin/docker run -ti --rm --privileged -v /:/host IMAGE /container/atomic-install [fedora@fed-atomic-01 ~]$ Host operations

For host related operation atomic acts as a wrapper for rpm-ostree allowing the same kind of operations.

[fedora@fed-atomic-01 ~]$ sudo atomic host -h usage: atomic host [-h] {rollback,status,upgrade,rebase,deploy,unlock,install,uninstall} ... positional arguments: {rollback,status,upgrade,rebase,deploy,unlock,install,uninstall} host commands rollback switch to alternate installed tree at next boot status list information about all deployments upgrade upgrade to the latest Atomic tree if one is available rebase Download and deploy a new origin refspec deploy deploy a specific commit unlock Make the current deployment mutable (for development or a hotfix) install Install a (layered) RPM package uninstall Remove a layered RPM package optional arguments: -h, --help show this help message and exit [fedora@fed-atomic-01 ~]$ Cockpit

Cockpit is a remote management interface of Linux hosts, I have written before about Cockpithere,here andhere. In an Atomic Host, Cockpit can be used to manage docker containers and Kubernetes clusters.

To use Cockpit in Atomic is as simple as sudo atomic run cockpit/ws .

[fedora@fed-atomic-01 ~]$ sudo atomic install cockpit/ws Using default tag: latest Trying to pull repository docker.io/cockpit/ws ... latest: Pulling from docker.io/cockpit/ws c46df4a5b63b: Pull complete 99ef0b2c8485: Pull complete 59a5aa6b0031: Pull complete 5951d07fb748: Pull complete 5f76b08ca3d3: Pull complete 29128c9a04f7: Pull complete 681bb27149fa: Pull complete 078f3e279249: Pull complete 080f6c78b22e: Pull complete d174142110f6: Pull complete 2599a2377eca: Pull complete Digest: sha256:b208b4e05c625837890345f816402f1e08ecc99fb569c29dca876e822dab4dbf Status: Downloaded newer image for docker.io/cockpit/ws:latest /usr/bin/docker run -ti --rm --privileged -v /:/host cockpit/ws /container/atomic-install + sed -e /pam_selinux/d -e /pam_sepermit/d /etc/pam.d/cockpit + mkdir -p /host/etc/cockpit/ws-certs.d + chmod 755 /host/etc/cockpit/ws-certs.d + chown root:root /host/etc/cockpit/ws-certs.d + mkdir -p /host/var/lib/cockpit + chmod 775 /host/var/lib/cockpit + chown root:wheel /host/var/lib/cockpit + /bin/mount --bind /host/etc/cockpit /etc/cockpit + /usr/sbin/remotectl certificate --ensure [fedora@fed-atomic-01 ~]$ [fedora@fed-atomic-01 ~]$ sudo atomic run cockpit/ws /usr/bin/docker run -d --privileged --pid=host -v /:/host cockpit/ws /container/atomic-run --local-ssh /usr/bin/docker run -d --privileged --pid=host -v /:/host cockpit/ws /container/atomic-run --local-ssh 5b300986736c4c4085d2c2c898ad3873f94236c0dd35e6689d2d83e2ff52a568 [fedora@fed-atomic-01 ~]$ [fedora@fed-atomic-01 ~]$ sudo docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 5b300986736c cockpit/ws "/container/atomic-ru" 13 seconds ago Up 13 seconds backstabbing_yonath [fedora@fed-atomic-01 ~]$

As you can see even the management applications in Atomic are run as containers.

Hope this article has been helpful to many of you to initiate into Atomic Hosts. Stay tuned for the next part of the series.

Juanma