Welcome!

@DevOpsSummit Authors: Liz McMillan, Flint Brenton, Pat Romanski, Elizabeth White, Cameron Van Orman

Related Topics: @DevOpsSummit, Linux Containers, Containers Expo Blog

@DevOpsSummit: Blog Feed Post

Docker Swarm | @DevOpsSummit #DevOps #API #Docker #Microservices

Docker Swarm distributes containers to multiple nodes using various deployment strategies in the cluster scheduler

Docker Swarm: Collecting Metrics, Events and Logs
By Stefan Thies

Docker Swarm is a cluster manager for Docker.  When accessed via the Docker API by Docker API Clients or Docker command line tools, a Docker Swarm cluster looks just like a single Docker Host.  Docker Swarm distributes containers to multiple nodes using various deployment strategies in the cluster scheduler.

Having in mind that a Swarm cluster looks like a single Docker Host from the API point of view, it should be very easy to monitor Docker Swarm with existing Docker monitoring tools!  Connecting a monitoring agent to the Swarm Master API endpoint should do the job, right? The Sematext Docker Agent could simply collect all container metrics, events and all logs from the Swarm Master - should be a piece of cake. Hmm, but could there a gotcha?  It turns out there is more than one:

  • If we deploy a single monitoring agent to the master node, it would miss host metrics for all other nodes because the Docker API doesn't provide any host metrics. We could also not see how much memory, disk space or CPU the Docker Swarm node itself consumes. Solution: deploy the monitoring agents to each node for collecting the metrics locally.
  • Assuming a larger cluster with a high volume of logs, events and metrics to collect, a single monitoring agent connected to the the master node would need to handle all operational data of the cluster.  This would work for a small cluster but such an architecture would obviously be destined for failure on larger clusters.  Guess what the solution is? It's much better having an agent running on each node and distributing the monitoring and logging work over all nodes. If you do it right from the beginning, there is no need to change the deployment strategy later, when the cluster scales out.

DockerSwarmMonitoring

Monitoring container running on each Docker node

In the following example we assume that the master and agent nodes have the UNIX socket enabled in Docker daemon settings. This can be achieved by using -engine-env ‘DOCKER_OPTS="-H unix:///var/run/docker.sock"‘ in the docker-machine create command. Use this Github Gist to create a Docker-Swarm Cluster with with enabled UNIX sockets. Later, we will see this helps simplify the deployment of any tool that needs to connect to the local Docker daemon - including monitoring and logging containers.

Let's see how to deploy Sematext Agent to each node in a Docker Swarm Cluster with UNIX socket enabled in Docker-Daemon as just described.

When we started to work on Swarm Monitoring our first question was "Does Docker Swarm provide a deployment strategy for running exactly one instance of a service on each node?" We checked the documentation, but no dice.  We found strategies like "spread, binpack, and random" (see https://docs.docker.com/swarm/scheduler/strategy/), but none of them would guarantee exactly one instance of a service on each node. The "spread" strategy spreads the containers evenly over all hosts. The "binpack" strategy fills up one node after another with containers, while "random" spreads containers randomly to nodes. There was seemingly no strategy suitable for monitoring services running only once on each node.

So how can we distribute the monitoring container to each host using Docker Swarm instead of bash script iterating over all nodes?  It turns out it's possible to define an affinity to ensure that containers that should run on the same host are scheduled together. In our case we use "anti-affinity" in the deployment strategy, which instructs Swarm not to deploy the container with Sematext Agent to hosts that already have that container running. In other words, it tells Docker Swarm to run no more than one Sematext Agent container on each Docker host.  To do that we define a docker-compose.yml file with the "anti-affinity" specified in the container environment section:

sematext-agent:
image: 'sematext/sematext-agent-docker:latest' environment:
- LOGSENE_TOKEN=3b549a2c-653a-4832-xxx
- SPM_TOKEN=fe31fc3a-4660-47c6-xxx
- affinity:container!=sematext-agent*
privileged: true
restart: always
volumes:
- '/var/run/docker.sock:/var/run/docker.sock'

Finally, we use the docker-compose command to scale out the Sematext Docker Agent and deploy it to all Swarm cluster nodes.  To do that we run:

eval $(docker-machine env swarm-master --swarm)
docker-compose up -d
# scale is == num nodes
docker-compose scale sematext-agent=$(docker-machine ls | grep swarm | grep Running | wc -l)

After running the above commands, Sematext Docker Agent will be running on each node and within a minute you will receive Host and Container Metrics for all containers, all their Logs and all Docker events from all nodes in your Docker Swarm cluster.  Complete visibility!

Bildschirmfoto 2016-01-12 um 15.36.01

Aggregated Metrics from all Docker Swarm nodes

Please note there are many ways to create a Swarm cluster and you might have another setup, such as:

  • TLS secured Docker daemon and no possibility to activate the unix socket: In this situation you have to deal with the existing Docker daemon setup, which typically uses TLS and authentication via certificates (for example, if you followed Docker's instructions to create Swarm clusters using Docker-Machine). When the Docker socket is secured with TLS, each client - including Sematext Docker Agent - needs the certificates for authentication. This involves a bunch of parameters such as "DOCKER_HOST", "DOCKER_CERT_PATH", "DOCKER_TLS_VERIFY" and mounting of the certificate into the container. In addition we should know to which Docker daemon the agent should be connected (typically port 2375 for TCP, 2376 for TLS on each node and port 3376 on Swarm Master nodes for the Swarm API). We made this scenario easy with a deployment script for the Sematext Agent with TLS options provided by Docker-Machine.
  • You use CoreOS to run Docker Swarm: In this case you could use fleet and systemd to distribute the agent to each node (simply install Sematext Agent with these instructions)

The deployment methods above should work for other monitoring tools or logging containers as well because most of such tools need to run on each node to collect the metrics locally.

If you have questions or special needs for monitoring more complex setups feel free to contact us. The Sematext Docker Agent is a turnkey-solution for Docker Logs, Metrics and Events - sign up here and give it a try (30-days free trial, no credit card needed).

Filed under: Logging, Monitoring Tagged: Containers, devops, docker, docker swarm, log management, logging, performance monitoring

More Stories By Sematext Blog

Sematext is a globally distributed organization that builds innovative Cloud and On Premises solutions for performance monitoring, alerting and anomaly detection (SPM), log management and analytics (Logsene), and search analytics (SSA). We also provide Search and Big Data consulting services and offer 24/7 production support for Solr and Elasticsearch.

@DevOpsSummit Stories
Join IBM November 1 at 21st Cloud Expo at the Santa Clara Convention Center in Santa Clara, CA, and learn how IBM Watson can bring cognitive services and AI to intelligent, unmanned systems. Cognitive analysis impacts today’s systems with unparalleled ability that were previously available only to manned, back-end operations. Thanks to cloud processing, IBM Watson can bring cognitive services and AI to intelligent, unmanned systems. Imagine a robot vacuum that becomes your personal assistant that knows everything and can respond to your emotions and verbal commands!
SYS-CON Events announced today that B2Cloud will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. B2Cloud specializes in IoT devices for preventive and predictive maintenance in any kind of equipment retrieving data like Energy consumption, working time, temperature, humidity, pressure, etc.
Today traditional IT approaches leverage well-architected compute/networking domains to control what applications can access what data, and how. DevOps includes rapid application development/deployment leveraging concepts like containerization, third-party sourced applications and databases. Such applications need access to production data for its test and iteration cycles. Data Security? That sounds like a roadblock to DevOps vs. protecting the crown jewels to those in IT.
SYS-CON Events announced today that Cedexis will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Cedexis is the leader in data-driven enterprise global traffic management. Whether optimizing traffic through datacenters, clouds, CDNs, or any combination, Cedexis solutions drive quality and cost-effectiveness.
Many companies start their journey to the cloud in the DevOps environment, where software engineers want self-service access to the custom tools and frameworks they need. Machine learning technology can help IT departments keep up with these demands. In his session at 21st Cloud Expo, Ajay Gulati, Co-Founder, CTO and Board Member at ZeroStack, will discuss the use of machine learning for automating provisioning of DevOps resources, taking the burden off IT teams.
SYS-CON Events announced today that NetApp has been named “Bronze Sponsor” of SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. NetApp is the data authority for hybrid cloud. NetApp provides a full range of hybrid cloud data services that simplify management of applications and data across cloud and on-premises environments to accelerate digital transformation. Together with their partners, NetApp empowers global organizations to unleash the full potential of their data to expand customer touchpoints, foster greater innovation and optimize their operations.
Is advanced scheduling in Kubernetes achievable? Yes, however, how do you properly accommodate every real-life scenario that a Kubernetes user might encounter? How do you leverage advanced scheduling techniques to shape and describe each scenario in easy-to-use rules and configurations? In his session at @DevOpsSummit at 21st Cloud Expo, Oleg Chunikhin, CTO at Kublr, will answer these questions and demonstrate techniques for implementing advanced scheduling. For example, using spot instances and cost-effective resources on AWS, coupled with the ability to deliver a minimum set of functionalities that cover the majority of needs – without configuration complexity.
SYS-CON Events announced today that Ryobi Systems will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Ryobi Systems Co., Ltd., as an information service company, specialized in business support for local governments and medical industry. We are challenging to achive the precision farming with AI. For more information, visit http://www.ryobi-sol.co.jp/en/.
SYS-CON Events announced today that mruby Forum will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. mruby is the lightweight implementation of the Ruby language. We introduce mruby and the mruby IoT framework that enhances development productivity. For more information, visit http://forum.mruby.org/.
With the rise of DevOps, containers are at the brink of becoming a pervasive technology in Enterprise IT to accelerate application delivery for the business. When it comes to adopting containers in the enterprise, security is the highest adoption barrier. Is your organization ready to address the security risks with containers for your DevOps environment? In his session at @DevOpsSummit at 21st Cloud Expo, Chris Van Tuin, Chief Technologist, NA West at Red Hat, will discuss: The top security risks with containers and how to manage these risks at scale including Images, Builds, Registry, Deployment, Hosts, Network, Storage, APIs, Monitoring/Logging, and Federation.
SYS-CON Events announced today that Mobile Create USA will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Mobile Create USA Inc. is an MVNO-based business model that uses portable communication devices and cellular-based infrastructure in the development, sales, operation and mobile communications systems incorporating GPS capability.
SYS-CON Events announced today that Enroute Lab will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Enroute Lab is an industrial design, research and development company of unmanned robotic vehicle system. For more information, please visit http://elab.co.jp/.
SYS-CON Events announced today that Nihon Micron will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Nihon Micron Co., Ltd. strives for technological innovation to establish high-density, high-precision processing technology for providing printed circuit board and metal mount RFID tags used for communication devices. For more information, visit http://www.nihon-micron.co.jp/.
SYS-CON Events announced today that Suzuki Inc. will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Suzuki Inc. is a semiconductor-related business, including sales of consuming parts, parts repair, and maintenance for semiconductor manufacturing machines, etc. It is also a health care business providing experimental research for dementia, etc. For more information, visit http://www.e-suzuki.co.jp/en/.
SYS-CON Events announced today that N3N will exhibit at SYS-CON's @ThingsExpo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. N3N’s solutions increase the effectiveness of operations and control centers, increase the value of IoT investments, and facilitate real-time operational decision making. N3N enables operations teams with a four dimensional digital “big board” that consolidates real-time live video feeds alongside IoT sensor data and analytics insights onto a single, holistic, display, focusing attention on what matters, when it matters.
Today most companies are adopting or evaluating container technology - Docker in particular - to speed up application deployment, drive down cost, ease management and make application delivery more flexible overall. As with most new architectures, this dream takes significant work to become a reality. Even when you do get your application componentized enough and packaged properly, there are still challenges for DevOps teams to making the shift to continuous delivery and achieving that reduction in cost and increase in speed. Sometimes in order to reduce complexity teams compromise features or change requirements
SYS-CON Events announced today that Massive Networks, that helps your business operate seamlessly with fast, reliable, and secure internet and network solutions, has been named "Exhibitor" of SYS-CON's 21st International Cloud Expo ®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. As a premier telecommunications provider, Massive Networks is headquartered out of Louisville, Colorado. With years of experience under their belt, their team of engineers can navigate the Carrier Ecosystem for your IT team acting as an extension of your business, producing a hassle-free experience.
SYS-CON Events announced today that SIGMA Corporation will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. uLaser flow inspection device from the Japanese top share to Global Standard! Then, make the best use of data to flip to next page. For more information, visit http://www.sigma-k.co.jp/en/.
SYS-CON Events announced today that Daiya Industry will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Daiya Industry specializes in orthotic support systems and assistive devices with pneumatic artificial muscles in order to contribute to an extended healthy life expectancy. For more information, please visit https://www.daiyak.co.jp/en/.
Most of the time there is a lot of work involved to move to the cloud, and most of that isn't really related to AWS or Azure or Google Cloud. Before we talk about public cloud vendors and DevOps tools, there are usually several technical and non-technical challenges that are connected to it and that every company needs to solve to move to the cloud. In his session at 21st Cloud Expo, Stefano Bellasio, CEO and founder of Cloud Academy Inc., will discuss what the tools, disciplines, and cultural aspects are that enterprise companies are considering to get to the cloud and eventually transform the way they build software and services.
SYS-CON Events announced today that Interface Corporation will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Interface Corporation is a company developing, manufacturing and marketing high quality and wide variety of industrial computers and interface modules such as PCIs and PCI express. For more information, visit http://www.interface-amita.com/aboutus/interface_profile.asp.
SYS-CON Events announced today that Keisoku Research Consultant Co. will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Keisoku Research Consultant, Co. offers research and consulting in a wide range of civil engineering-related fields from information construction to preservation of cultural properties. For more information, visit http://www.krcnet.co.jp/eng_site/e_index.htm.
SYS-CON Events announced today that MIRAI Inc. will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. MIRAI Inc. are IT consultants from the public sector whose mission is to solve social issues by technology and innovation and to create a meaningful future for people.
SYS-CON Events announced today that Fusic will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Fusic Co. provides mocks as virtual IoT devices. You can customize mocks, and get any amount of data at any time in your test. For more information, visit https://fusic.co.jp/english/.
21st International Cloud Expo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterprises are using some form of XaaS – software, platform, and infrastructure as a service.