Episode #341: Introduction to Using Squid Web Proxy Server
An HTTP proxy server is basically a program that accepts requests from clients for URLs, fetches them on behalf of the client, and returns the results to the client.
Proxies are used on networks where clients do not have direct access to the Internet but still need to be able to view web pages. A proxy is also used for caching commonly requested pages so that if more than one client wants to view the same page it only has to be downloaded once.
Many companies and organizations have their firewalls set up to block all incoming and outgoing traffic by systems on internal LANs. This may be done for security reasons, or to limit what employees can access on the Internet. Because being able to view web pages is extremely useful, a proxy is often set up so that websites can be accessed through it.
Large organizations and ISPs with many client PCs accessing the web may also want to run a proxy server to reduce the load on their networks. Because one of the main tasks of a proxy is caching pages requested by clients, any page asked for more than once will be returned from the cache instead of being fetched from the originating server.
For this reason clients systems are often configured or forced to use a caching proxy to access the web. A proxy is only useful if client browsers are configured to use it instead of connecting to web sites directly.
Fortunately, every web browser in existence, and almost all programs that download files via HTTP for various purposes, can be configured to use a proxy. Even encrypted SSL connections can be handled by a proxy, even though it cannot decrypt the request. Instead, the proxy simply forwards all data from the client to the destination server and back again. It is open source and is freely available for download from www. Squid supports both proxying, caching and HTTP acceleration, and has a large number of configuration options to control the behavior of these features.
Squid reads its configuration from the text file squid. This file consists of a series of directives, one per line, each of which has a name and value. Each directive sets some option, such as the TCP port to listen on or a directory to store cached files in. Webmin's Squid module edits this file directly, ignoring any comments or directives that it does not understand. Many versions of Squid have been released over the years, each of which has supported different configuration directives or assigned different meanings to the same directives.
This means that a squid. Fortunately, Webmin knows which directives each release supports and only allows editing of those that are known to the running version of Squid.
Cached web pages are stored in files in a multi-level directory structure for increased filesystem performance. Squid can be configured to use multiple separate cache directories, so that you can spread files over different disks to improve performance. Every time a cacheable page is requested it is stored in a file, so that when a subsequent request for the same page arrives the file can be read and the data served from it.
Because some web pages change over time or are even dynamically generatedSquid keeps track of the last-modified and expiry dates of web pages so that it can clear data from the cache when it is out of date. The actual program that handles client requests is a permanently running server process called squid. It may also start several other sub-processes for tasks such as DNS lookups or client authentication, but all the actual HTTP protocol processing is done in the single master process.
Unlike other similar servers such as Apache or Sendmail, Squid does not start or use sub-processes to handle client requests. Squid can be compiled on all the flavors of Unix that Webmin supports, and works almost identically on all of them.
This means that the Webmin module's user interface is the same across operating systems as well, with the exception of the default paths that it uses for the Squid programs and configuration files.Supported OS:. Home Docs API. The amount of traffic sent to clients in responses that are cache hits Shown as kibibyte. The number of requests forwarded to origin servers or neighbor caches for all server-side protocols. Shown as request. The number of server-side requests all protocols that resulted in some kind of error.
Shown as error. The amount of traffic read from the server-side for all protocols.
Squid Proxy Server
Shown as kibibyte. The number of server-side requests to HTTP servers, including neighbor caches. The amount of traffic read from HTTP origin servers and neighbor caches. The amount of traffic written to HTTP origin servers and neighbor caches.
The number of requests sent to FTP servers that resulted in an error. The amount of traffic read from FTP servers, including control channel traffic. The amount of traffic written to FTP servers, including control channel traffic. The number of "other" server-side requests. The number of ICP messages sent to neighbors. This includes both queries and replies but doesn't include HTCP messages. Shown as message.
The number of ICP messages received from neighbors, including both queries and replies Shown as message. The number of times that Squid timed out waiting for ICP replies to arrive. The number of times Squid queued an ICP message after the initial attempt to send failed. The amount of traffic sent in all ICP messages, including both queries and replies.If your network configuration restricted outbound traffic, proxy all Agent traffic through one or several hosts that have more permissive outbound policies.
Traditional web proxies are supported natively by the Agent. If you need to connect to the Internet through a proxy, edit your Agent configuration file. Set different proxy servers for https and http requests in your Agent datadog. The Agent uses https to send data to Datadog, but integrations might use http to gather metrics.
No matter the proxied requests, you can activate SSL on your proxy server. Below are some configuration examples for your datadog. As such, when using a proxy for https requests, there is no need to use an HTTPS proxy in order to have encrypted communication between the Agent and Datadog. Environment variables have precedence over values in the datadog. If the environment variables are present with an empty value e. The Agent uses these if present. Be careful, as such variables also impact every requests from integrations, including orchestrators like Docker, ECS, and Kubernetes.
Do not forget to restart the Agent for the new settings to take effect. While HAProxy is usually used as a load balancer to distribute incoming requests to pools servers, you can also use it to proxy Agent traffic to Datadog from hosts that have no outside connectivity. This is the best option if you do not have a web proxy readily available in your network, and you wish to proxy a large number of Agents.
In some cases, a single HAProxy instance is sufficient to handle local Agent traffic in your network-each proxy can accommodate upwards of Agents. Be aware that this figure is a conservative estimate based on the performance of m3. Numerous network-related variables can influence load on proxies.
As always, deploy under a watchful eye. Visit HAProxy documentation for additional information. HAProxy should be installed on a host that has connectivity to Datadog. Use the following configuration file if you do not already have it configured.
HAProxy 1. To send traces or processes through the proxy, setup the following in the datadog. Then edit the datadog. This is needed to make the Agent ignore the discrepancy between the hostname on the SSL certificate app. Finally restart the Agent.
Edit your supervisor configuration to disable SSL certificate verification. This is needed to prevent Python from complaining about the discrepancy between the hostname on the SSL certificate app. The supervisor configuration found at:. For the Windows Agent, edit your configuration file datadog. This example nginx. To use the Datadog Agent v6 as the logs collector, instruct the Agent to use the newly created proxy instead of establishing a connection directly with the logs intake by updating datadog.
Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Essentially I use this proxy so that app containers on my local docker and the browser pod Selenium on another host use the same network for testing so that the remote browser can access the app host.
But with my current setup, when I run my tests the browser starts up on the remote host and then after a bit fails the test. So I assume that there is an issue with my squid proxy config. I use the default config and on the docker hub site it says. Please note that the stock configuration available with the container is set for local access, you may need to tweak it if your network scenario is different.
I'm not really sure how my network scenario is different. What should I be looking into for more information? Learn more. Asked 2 years, 3 months ago.
Active 2 years, 3 months ago. Viewed times. I use the default config and on the docker hub site it says Please note that the stock configuration available with the container is set for local access, you may need to tweak it if your network scenario is different.
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Feedback on Q2 Community Roadmap.Linaro Automated Validation Architecture LAVA is a software project that is used to automate running jobs on physical hosts in a board farm, often for the purposes of testing and continuous integration CI.
Docker is a widely used software project that makes packaging, managing, and deploying software easier. A more modern approach is to deploy using Docker containers. This is an approach that is under active development, as it was only recently added as a supported way to run LAVA.
One more digression before getting into the details: LAVA has a steep learning curve. It has a lot of components, and the things it automates embedded boards are also complicated. The standard advice is to start slowly with the most common and easiest use-cases before moving to more advanced tasks.
Heed this advice! To that end, the first recommended use-case is to install lava-server and lava-dispatcher to the same host, and add a QEMU virtual device. This is a nice first goal because it does not require hardware - the details about physically attaching and dealing with hardware can be deferred until the basic LAVA stuff is understood and working. Besides, QEMU devices are super handy to use in testing. This is where Docker starts to come in handy.
However, if you are using Docker - you just need a host with Docker installed. Without additional configuration, not much will happen. We need to deal with all of the state of the containers; things like the database and the job output directory. We also need to handle the configuration of the containers, in a way that is persistent and in source control so that changes can be tracked over time. For configuration, the general strategy is to set and pass environmental variables into the containers at runtime to control their behavior.
When environmental variables are insufficient, configuration files can be mounted in using volume mounts. For state, docker volumes should be used to save the contents of the database and job output on the docker host, rather than inside the docker container. Docker Compose is a python tool that allows us to put our docker configuration into a yaml file - making it easier to manage, and more portable, than things like shell scripts.
An example docker-compose.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Skip to content. Permalink Dismiss Join GitHub today GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.
Branch: master. Find file Copy path. Cannot retrieve contributors at this time. Raw Blame History. It should point to a credential cache with a valid TGT. It may also contain an unencrypted private key to use. You can use it for explicitly specifying the host header or adding headers for authorization purposes. This overrides any default headers. Set path if the type is file. You signed in with another tab or window. Reload to refresh your session.
You signed out in another tab or window. If you want to resolve the domains on the proxy. The hostname or ip address of the squid server. The port where the squid server is listening. List of tags to attach to every metric, event, and service check emitted by this Integration.
The username to use if services are behind basic auth. If your services uses NTLM authentication, you can. The password to use if services are behind basic or NTLM auth. If your service uses Kerberos authentication, you can specify the Kerberos.
Set an explicit principal, to force Kerberos to look for a matching credential cache for the named user. Set the path to your Kerberos key tab file. Instructs the check to validate the TLS certificate of services.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.
If nothing happens, download GitHub Desktop and try again. If nothing happens, download Xcode and try again.
If nothing happens, download the GitHub extension for Visual Studio and try again. Dockerfile to create a Docker container image for Squid proxy server.
It reduces bandwidth and improves response times by caching and reusing frequently-requested web pages. Squid has extensive access controls and makes a great server accelerator.
Before reporting your issue please try updating Docker to the latest version and check if it resolves the issue. Refer to the Docker installation guide for instructions. SELinux users should try disabling SELinux using the command setenforce 0 to see if it resolves the issue. If the above recommendations do not help then report your issue along with the following information:. Automated builds of the image are available on Dockerhub and is the recommended method of installation.
Note : Builds are also available on Quay. Alternatively, you can use the sample docker-compose. You can customize the launch command of the Squid server by specifying arguments to squid on the docker run command. For example the following command prints the help menu of squid command:.
The Quickstart command already mounts a volume for persistence. SELinux users should update the security context of the host mountpoint so that it plays nicely with Docker:. Squid is a full featured caching proxy server and a large number of configuration parameters.
To reload the Squid configuration on a running instance you can send the HUP signal to the container. If you are using Linux then you can also add the following lines to your. For example, if you want to tail the access logs:. For debugging and maintenance purposes you may want access the containers shell. If you are using Docker version 1.
Agent proxy configuration
Skip to content. Dismiss Join GitHub today GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Sign up. Shell Dockerfile Makefile. Shell Branch: master. Find file. Sign in Sign up. Go back. Launching Xcode If nothing happens, download Xcode and try again. Latest commit. Latest commit b Jul 6, Contributing If you find this image useful here's how you can help: Send a pull request with your awesome features and bug fixes Help users resolve their issues.
Support the development of this image with a donation Issues Before reporting your issue please try updating Docker to the latest version and check if it resolves the issue. If the above recommendations do not help then report your issue along with the following information: Output of the docker version and docker info commands The docker run command or docker-compose.