--- /dev/null
+
+.. _containter_orchestration_in_csit:
+
+Container Orchestration in CSIT
+===============================
+
+Overview
+--------
+
+Linux Containers
+~~~~~~~~~~~~~~~~
+
+Linux Containers is an OS-level virtualization method for running
+multiple isolated Linux systems (containers) on a compute host using a
+single Linux kernel. Containers rely on Linux kernel cgroups
+functionality for controlling usage of shared system resources (i.e.
+CPU, memory, block I/O, network) and for namespace isolation. The latter
+enables complete isolation of applications' view of operating
+environment, including process trees, networking, user IDs and mounted
+file systems.
+
+:abbr:`LXC (Linux Containers)` combine kernel's cgroups and support for isolated
+namespaces to provide an isolated environment for applications. Docker
+does use LXC as one of its execution drivers, enabling image management
+and providing deployment services. More information in [lxc]_, [lxc-namespace]_
+and [stgraber]_.
+
+Linux containers can be of two kinds: privileged containers and
+unprivileged containers.
+
+Unprivileged Containers
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Running unprivileged containers is the safest way to run containers in a
+production environment. From LXC 1.0 one can start a full system
+container entirely as a user, allowing to map a range of UIDs on the
+host into a namespace inside of which a user with UID 0 can exist again.
+In other words an unprivileged container does mask the userid from the
+host, making it impossible to gain a root access on the host even if a
+user gets root in a container. With unprivileged containers, non-root
+users can create containers and will appear in the container as the
+root, but will appear as userid <non-zero> on the host. Unprivileged
+containers are also better suited to supporting multi-tenancy operating
+environments. More information in [lxc-security]_ and [stgraber]_.
+
+Privileged Containers
+~~~~~~~~~~~~~~~~~~~~~
+
+Privileged containers do not mask UIDs, and container UID 0 is mapped to
+the host UID 0. Security and isolation is controlled by a good
+configuration of cgroup access, extensive AppArmor profile preventing
+the known attacks as well as container capabilities and SELinux. Here a
+list of applicable security control mechanisms:
+
+- Capabilities - keep (whitelist) or drop (blacklist) Linux capabilities,
+ [capabilities]_.
+- Control groups - cgroups, resource bean counting, resource quotas, access
+ restrictions, [cgroup1]_, [cgroup2]_.
+- AppArmor - apparmor profiles aim to prevent any of the known ways of
+ escaping a container or cause harm to the host, [apparmor]_.
+- SELinux - Security Enhanced Linux is a Linux kernel security module
+ that provides similar function to AppArmor, supporting access control
+ security policies including United States Department of Defense–style
+ mandatory access controls. Mandatory access controls allow an
+ administrator of a system to define how applications and users can
+ access different resources such as files, devices, networks and inter-
+ process communication, [selinux]_.
+- Seccomp - secure computing mode, enables filtering of system calls,
+ [seccomp]_.
+
+More information in [lxc-security]_ and [lxc-sec-features]_.
+
+**Linux Containers in CSIT**
+
+CSIT is using Privileged Containers as the ``sysfs`` is mounted with RW
+access. Sysfs is required to be mounted as RW due to VPP accessing
+:command:`/sys/bus/pci/drivers/uio_pci_generic/unbind`. This is not the case of
+unprivileged containers where ``sysfs`` is mounted as read-only.
+
+
+Orchestrating Container Lifecycle Events
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Following Linux container lifecycle events need to be addressed by an
+orchestration system:
+
+1. Acquire - acquiring/downloading existing container images via
+ :command:`docker pull` or :command:`lxc-create -t download`.
+
+2. Build - building a container image from scratch or another
+ container image via :command:`docker build <dockerfile/composefile>` or
+ customizing LXC templates in
+ `https://github.com/lxc/lxc/tree/master/templates`_
+
+3. (Re-)Create - creating a running instance of a container application
+ from anew, or re-creating one that failed. A.k.a. (re-)deploy via
+ :command:`docker run` or :command:`lxc-start`
+
+4. Execute - execute system operations within the container by attaching to
+ running container. THis is done by :command:`lxc-attach` or
+ :command:`docker exec`
+
+5. Distribute - distributing pre-built container images to the compute
+ nodes. Currently not implemented in CSIT.
+
+
+Container Orchestration Systems Used in CSIT
+--------------------------------------------
+
+Current CSIT testing framework integrates following Linux container
+orchestration mechanisms:
+
+- LXC/Docker for complete VPP container lifecycle control.
+- Combination of Kubernetes (container orchestration), Docker (container
+ images) and Ligato (container networking).
+
+LXC
+~~~
+
+LXC is the well-known and heavily tested low-level Linux container
+runtime [lxc-source]_, that provides a userspace interface for the Linux kernel
+containment features. With a powerful API and simple tools, LXC enables
+Linux users to easily create and manage system or application
+containers. LXC uses following kernel features to contain processes:
+
+- Kernel namespaces: ipc, uts, mount, pid, network and user.
+- AppArmor and SELinux security profiles.
+- Seccomp policies.
+- Chroot.
+- Cgroups.
+
+CSIT uses LXC runtime and LXC usertools to test VPP data plane performance in
+a range of virtual networking topologies.
+
+**Known Issues**
+
+- Current CSIT restriction: only single instance of lxc runtime due to
+ the cgroup policies used in CSIT. There is plan to add the capability into
+ code to create cgroups per container instance to address this issue. This sort
+ of functionality is better supported in LXC 2.1 but can be done is current
+ version as well.
+
+**Open Questions**
+
+- CSIT code is currently using cgroup to pin lxc data plane thread to
+ cpu cores after lxc container is created. In the future may find a
+ more universal way to do it.
+
+Docker
+~~~~~~
+
+Docker builds on top of Linux kernel containment features, and
+offers a high-level tool for wrapping the processes, maintaining and
+executing them in containers [docker]_. Currently it using *runc* a CLI tool for
+spawning and running containers according to the `OCI specification
+<https://www.opencontainers.org/>`_
+
+A Docker container image is a lightweight, stand-alone, executable
+package of a piece of software that includes everything needed to run
+it: code, runtime, system tools, system libraries, settings.
+
+CSIT uses Docker to manage the maintenance and execution of
+containerized applications used in CSIT performance tests.
+
+- Data plane thread pinning to CPU cores - Docker CLI and/or Docker
+ configuration file controls the range of CPU cores the Docker image
+ must run on. VPP thread pinning defined vpp startup.conf.
+
+
+Kubernetes
+~~~~~~~~~~
+
+Kubernetes [k8s-doc]_, or K8s, is a production-grade container orchestration
+platform for automating the deployment, scaling and operating
+application containers. Kubernetes groups containers that make up an
+application into logical units, pods, for easy management and discovery.
+K8s pod definitions including compute resource allocation is provided in
+.yaml files.
+
+CSIT uses K8s and its infrastructure components like etcd to control all
+phases of container based virtualized network topologies.
+
+**Known Issues**
+
+- Unable to properly pin k8s pods and containers to cpu cores. This will be
+ addressed in Kubernetes 1.8+ in alpha testing.
+
+**Open Questions**
+
+- Clarify the functions provided by Contiv and Calico in Ligato system?
+
+Ligato
+~~~~~~
+
+Ligato [ligato]_ is an open-source project developing a set of cloud-native
+tools for orchestrating container networking. Ligato integrates with FD.io VPP
+using goVPP [govpp]_ and vpp-agent [vpp-agent]_.
+
+**Known Issues**
+
+**Open Questions**
+
+- Currently using a separate LF Jenkins job for building csit-centric
+ vpp_agent docker images vs. dockerhub/ligato ones.
+
+Implementation
+--------------
+
+CSIT container orchestration is implemented in CSIT Level-1 keyword
+Python libraries following the Builder design pattern. Builder design
+pattern separates the construction of a complex object from its
+representation, so that the same construction process can create
+different representations e.g. LXC, Docker, other.
+
+CSIT Robot Framework keywords are then responsible for higher level
+lifecycle control of of the named container groups. One can have
+multiple named groups, with 1..N containers in a group performing
+different role/functionality e.g. NFs, Switch, Kafka bus, ETCD
+datastore, etc. ContainerManager class acts as a Director and uses
+ContainerEngine class that encapsulate container control.
+
+Current CSIT implementation is illustrated using UML Class diagram:
+
+1. Acquire
+2. Build
+3. (Re-)Create
+4. Execute
+
+::
+
+ +-----------------------------------------------------------------------+
+ | RF Keywords (high level lifecycle control) |
+ +-----------------------------------------------------------------------+
+ | Construct VNF containers on all DUTs |
+ | Acquire all '${group}' containers |
+ | Create all '${group}' containers |
+ | Install all '${group}' containers |
+ | Configure all '${group}' containers |
+ | Stop all '${group}' containers |
+ | Destroy all '${group}' containers |
+ +-----------------+-----------------------------------------------------+
+ | 1
+ |
+ | 1..N
+ +-----------------v-----------------+ +--------------------------+
+ | ContainerManager | | ContainerEngine |
+ +-----------------------------------+ +--------------------------+
+ | __init()__ | | __init(node)__ |
+ | construct_container() | | acquire(force) |
+ | construct_containers() | | create() |
+ | acquire_all_containers() | | stop() |
+ | create_all_containers() | 1 1 | destroy() |
+ | execute_on_container() <>-------| info() |
+ | execute_on_all_containers() | | execute(command) |
+ | install_vpp_in_all_containers() | | system_info() |
+ | configure_vpp_in_all_containers() | | install_supervisor() |
+ | stop_all_containers() | | install_vpp() |
+ | destroy_all_containers() | | restart_vpp() |
+ +-----------------------------------+ | create_vpp_exec_config() |
+ | create_vpp_startup_config|
+ | is_container_running() |
+ | is_container_present() |
+ | _configure_cgroup() |
+ +-------------^------------+
+ |
+ |
+ |
+ +----------+---------+
+ | |
+ +------+-------+ +------+-------+
+ | LXC | | Docker |
+ +--------------+ +--------------+
+ | (inherinted) | | (inherinted) |
+ +------+-------+ +------+-------+
+ | |
+ +---------+---------+
+ |
+ | constructs
+ |
+ +---------v---------+
+ | Container |
+ +-------------------+
+ | __getattr__(a) |
+ | __setattr__(a, v) |
+ +-------------------+
+
+Sequentional diagram that illustrates the creation of a single container.
+
+.. mk: what "RF KW" is meant below?
+.. mk: the flow sequence should adhere to the lifecycle events listed earlier in this doc.
+
+::
+
+ Legend:
+ e = engine [Docker|LXC]
+ .. = kwargs (variable number of keyword argument)
+
+ +-------+ +------------------+ +-----------------+
+ | RF KW | | ContainerManager | | ContainerEngine |
+ +---+---+ +--------+---------+ +--------+--------+
+ | | |
+ | 1: new ContainerManager(e) | |
+ +-+---------------------------->+-+ |
+ |-| |-| 2: new ContainerEngine |
+ |-| |-+----------------------->+-+
+ |-| |-| |-|
+ |-| +-+ +-+
+ |-| | |
+ |-| 3: construct_container(..) | |
+ |-+---------------------------->+-+ |
+ |-| |-| 4: init() |
+ |-| |-+----------------------->+-+
+ |-| |-| |-| 5: new +-------------+
+ |-| |-| |-+-------->| Container A |
+ |-| |-| |-| +-------------+
+ |-| |-|<-----------------------+-|
+ |-| +-+ +-+
+ |-| | |
+ |-| 6: acquire_all_containers() | |
+ |-+---------------------------->+-+ |
+ |-| |-| 7: acquire() |
+ |-| |-+----------------------->+-+
+ |-| |-| |-|
+ |-| |-| |-+--+
+ |-| |-| |-| | 8: is_container_present()
+ |-| |-| True/False |-|<-+
+ |-| |-| |-|
+ |-| |-| |-|
+ +---------------------------------------------------------------------------------------------+
+ | |-| ALT [isRunning & force] |-| |-|--+ |
+ | |-| |-| |-| | 8a: destroy() |
+ | |-| |-| |-<--+ |
+ +---------------------------------------------------------------------------------------------+
+ |-| |-| |-|
+ |-| +-+ +-+
+ |-| | |
+ |-| 9: create_all_containers() | |
+ |-+---------------------------->+-+ |
+ |-| |-| 10: create() |
+ |-| |-+----------------------->+-+
+ |-| |-| |-+--+
+ |-| |-| |-| | 11: wait('RUNNING')
+ |-| |-| |-<--+
+ |-| +-+ +-+
+ |-| | |
+ +---------------------------------------------------------------------------------------------+
+ | |-| ALT | | |
+ | |-| (install_vpp, configure_vpp) | | |
+ | |-| | | |
+ +---------------------------------------------------------------------------------------------+
+ |-| | |
+ |-| 12: destroy_all_containers() | |
+ |-+---------------------------->+-+ |
+ |-| |-| 13: destroy() |
+ |-| |-+----------------------->+-+
+ |-| |-| |-|
+ |-| +-+ +-+
+ |-| | |
+ +++ | |
+ | | |
+ + + +
+
+Container Data Structure
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Container is represented in Python L1 library as a separate Class with instance
+variables and no methods except overriden ``__getattr__`` and ``__setattr__``.
+Instance variables are assigned to container dynamically during the
+``construct_container(**kwargs)`` call and are passed down from the RF keyword.
+
+Usage example:
+
+.. code-block:: robotframework
+
+ | Construct VNF containers on all DUTs
+ | | [Arguments] | ${technology} | ${image} | ${cpu_count}=${1} | ${count}=${1}
+ | | ...
+ | | ${group}= | Set Variable | VNF
+ | | ${guest_dir}= | Set Variable | /mnt/host
+ | | ${host_dir}= | Set Variable | /tmp
+ | | ${skip_cpus}= | Evaluate | ${vpp_cpus}+${system_cpus}
+ | | Import Library | resources.libraries.python.ContainerUtils.ContainerManager
+ | | ... | engine=${technology} | WITH NAME | ${group}
+ | | ${duts}= | Get Matches | ${nodes} | DUT*
+ | | :FOR | ${dut} | IN | @{duts}
+ | | | {env}= | Create List | LC_ALL="en_US.UTF-8"
+ | | | ... | DEBIAN_FRONTEND=noninteractive | ETCDV3_ENDPOINTS=172.17.0.1:2379
+ | | | ${cpu_node}= | Get interfaces numa node | ${nodes['${dut}']}
+ | | | ... | ${dut1_if1} | ${dut1_if2}
+ | | | Run Keyword | ${group}.Construct containers
+ | | | ... | name=${dut}_${group}
+ | | | ... | node=${nodes['${dut}']}
+ | | | ... | host_dir=${host_dir}
+ | | | ... | guest_dir=${guest_dir}
+ | | | ... | image=${image}
+ | | | ... | cpu_count=${cpu_count}
+ | | | ... | cpu_skip=${skip_cpus}
+ | | | ... | smt_used=${False}
+ | | | ... | cpuset_mems=${cpu_node}
+ | | | ... | cpu_shared=${False}
+ | | | ... | env=${env}
+
+Mandatory parameters to create standalone container are: ``node``, ``name``,
+``image`` [image-var]_, ``cpu_count``, ``cpu_skip``, ``smt_used``,
+``cpuset_mems``, ``cpu_shared``.
+
+There is no parameters check functionality. Passing required arguments is in
+coder responsibility. All the above parameters are required to calculate the
+correct cpu placement. See documentation for the full reference.
+
+Kubernetes
+~~~~~~~~~~
+
+Kubernetes is implemented as separate library ``KubernetesUtils.py``,
+with a class with the same name. This utility provides an API for L2
+Robot Keywords to control ``kubectl`` installed on each of DUTs. One
+time initialization script, ``resources/libraries/bash/k8s_setup.sh``
+does reset/init kubectl, applies Calico v2.4.1 and initializes the
+``csit`` namespace. CSIT namespace is required to not to interfere with
+existing setups and it further simplifies apply/get/delete
+Pod/ConfigMap operations on SUTs.
+
+Kubernetes utility is based on YAML templates to avoid crafting the huge
+YAML configuration files, what would lower the readability of code and
+requires complicated algorithms. The templates can be found in
+``resources/templates/kubernetes`` and can be leveraged in the future
+for other separate tasks.
+
+Two types of YAML templates are defined:
+
+- Static - do not change between deployments, that is infrastructure
+ containers like Kafka, Calico, ETCD.
+
+- Dynamic - per test suite/case topology YAML files e.g. SFC_controller,
+ VNF, VSWITCH.
+
+Making own python wrapper library of ``kubectl`` instead of using the
+official Python package allows to control and deploy environment over
+the SSH library without the need of using isolated driver running on
+each of DUTs.
+
+Ligato
+~~~~~~
+
+Ligato integration does require to compile the ``vpp-agent`` tool and build the
+bundled Docker image. Compilation of ``vpp-agent`` depends on specific VPP. In
+``ligato/vpp-agent`` repository there are well prepared scripts for building the
+Docker image. Building docker image is possible via series of commands:
+
+::
+
+ git clone https://github.com/ligato/vpp-agent
+ cd vpp_agent/docker/dev_vpp_agent
+ sudo docker build -t dev_vpp_agent --build-arg AGENT_COMMIT=<agent commit id>\
+ --build-arg VPP_COMMIT=<vpp commit id> --no-cache .
+ sudo ./shrink.sh
+ cd ../prod_vpp_agent
+ sudo ./build.sh
+ sudo ./shrink.sh
+
+CSIT requires Docker image to include the desired VPP version (per patch
+testing, nightly testing, on demand testing).
+
+The entire build process of building ``dev_vpp_agent`` image heavily depends
+on internet connectivity and also takes a significant amount of time (~1-1.5h
+based on internet bandwidth and allocated resources). The optimal solution would
+be to build the image on jenkins slave, transfer the Docker image to DUTs and
+execute separate suite of tests.
+
+To adress the amount of time required to build ``dev_vpp_agent`` image, we can
+pull existing specific version of ```dev_vpp_agent``` and exctract the
+```vpp-agent``` from it.
+
+We created separate sets of Jenkins jobs, that will be executing following:
+
+1. Clone latest CSIT and Ligato repositaries.
+2. Pull specific version of ``dev_vpp_agent`` image from Dockerhub.
+3. Build ``prod_vpp_image`` Docker image from ``dev_vpp_agent`` image.
+4. Shrink image using ``docker/dev_vpp_agent/shrink.sh`` script.
+5. Transfer ``prod_vpp_agent_shrink`` image to DUTs.
+6. Execute subset of performance tests designed for Ligato testing.
+
+::
+
+ +-----------------------------------------------+
+ | ubuntu:16.04 <-----| Base image on Dockerhub
+ +------------------------^----------------------+
+ |
+ |
+ +------------------------+----------------------+
+ | ligato/dev_vpp_agent <------| Pull this image from
+ +------------------------^----------------------+ | Dockerhub ligato/dev_vpp_agent:<version>
+ |
+ | Extract agent.tar.gz from dev_vpp_agent
+ +------------------------+----------------------+
+ | prod_vpp_agent <------| Build by passing own
+ +-----------------------------------------------+ | vpp.tar.gz (from nexus
+ | or built by JJB) and
+ | agent.tar.gz extracted
+ | from ligato/dev_vpp_agent
+
+
+Approximate size of vnf-agent docker images:
+
+::
+
+ REPOSITORY TAG IMAGE ID CREATED SIZE
+ dev_vpp_agent latest 442771972e4a 8 hours ago 3.57 GB
+ dev_vpp_agent_shrink latest bd2e76980236 8 hours ago 1.68 GB
+ prod_vpp_agent latest e33a5551b504 2 days ago 404 MB
+ prod_vpp_agent_shrink latest 446b271cce26 2 days ago 257 MB
+
+In CSIT we need to create separate performance suite under
+``tests/kubernetes/perf`` which contains modified Suite setup in comparison
+to standard perf tests. This is due to reason that VPP will act as vswitch in
+Docker image and not as standalone installed service.
+
+Tested Topologies
+~~~~~~~~~~~~~~~~~
+
+Listed CSIT container networking test topologies are defined with DUT
+containerized VPP switch forwarding packets between NF containers. Each
+NF container runs their own instance of VPP in L2XC configuration.
+
+Following container networking topologies are tested in CSIT |release|:
+
+- LXC topologies:
+
+ - eth-l2xcbase-eth-2memif-1lxc.
+ - eth-l2bdbasemaclrn-eth-2memif-1lxc.
+
+- Docker topologies:
+
+ - eth-l2xcbase-eth-2memif-1docker.
+
+- Kubernetes/Ligato topologies:
+
+ - eth-l2xcbase-eth-2memif-1vnf.
+ - eth-l2xcbase-eth-4memif-2vnf.
+ - eth-l2bdbasemaclrn-eth-2memif-1vnf.
+ - eth-l2bdbasemaclrn-eth-4memif-2vnf.
+
+
+References
+----------
+
+.. [lxc] `Linux Containers <https://linuxcontainers.org/>`_
+.. [lxc-namespace] `Resource management: Linux kernel Namespaces and cgroups <https://www.cs.ucsb.edu/~rich/class/cs293b-cloud/papers/lxc-namespace.pdf>`_.
+.. [stgraber] `LXC 1.0: Blog post series <https://stgraber.org/2013/12/20/lxc-1-0-blog-post-series/>`_.
+.. [lxc-security] `Linux Containers Security <https://linuxcontainers.org/lxc/security/>`_.
+.. [capabilities] `Linux manual - capabilities - overview of Linux capabilities http://man7.org/linux/man-pages/man7/capabilities.7.html`_.
+.. [cgroup1] `Linux kernel documentation: cgroups <https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt>`_.
+.. [cgroup2] `Linux kernel documentation: Control Group v2 <https://www.kernel.org/doc/Documentation/cgroup-v2.txt>`_.
+.. [selinux] `SELinux Project Wiki <http://selinuxproject.org/page/Main_Page>`_.
+.. [lxc-sec-features] `LXC 1.0: Security features <https://stgraber.org/2014/01/01/lxc-1-0-security-features/>`_.
+.. [lxc-source] `Linux Containers source <https://github.com/lxc/lxc>`_.
+.. [apparmor] `Ubuntu AppArmor <https://wiki.ubuntu.com/AppArmor>`_.
+.. [seccomp] `SECure COMPuting with filters <https://www.kernel.org/doc/Documentation/prctl/seccomp_filter.txt>`_.
+.. [docker] `Docker <https://www.docker.com/what-docker>`_.
+.. [k8s-doc] `Kubernetes documentation <https://kubernetes.io/docs/home/>`_.
+.. [ligato] `Ligato <https://github.com/ligato>`_.
+.. [govpp] `FD.io goVPP project <https://wiki.fd.io/view/GoVPP>`_.
+.. [vpp-agent] `Ligato vpp-agent <https://github.com/ligato/vpp-agent>`_.
+.. [image-var] Image parameter is required in initial commit version. There is plan to implement container build class to build Docker/LXC image.
Code Review / csit.git / commitdiff