SMTP mail relays exposed to the internet typically use a combination of SSL and authenticated SMTP to avoid abuse by malicious actors.
This is an excellent choice from a security perspective, but makes smoke testing a bit more complex than just opening telnet.
Continue reading “Ubuntu: Testing authenticated SMTP over TLS/SSL”
Ansible is an agentless configuration management tool that helps operations teams manage installation, patching, and command execution across a set of servers.
Ansible was started as a Linux only solution, leveraging ssh to provide a management channel to a target server. However, starting at Ansible 1.7, support for Windows hosts was added by using Powershell remoting over WinRM.
Continue reading “Ansible: Managing a Windows host using Ansible”
ElasticSearch very often serves as a repository for monitoring, logging, and business data. As such, integrations with external system are a requirement.
The Go programming language with its convenient deployment binary and rich set of packages can easily serve as a bridge between these systems and the ElasticSearch server.
We will use the olivere/elastic package for this purpose, it is well maintained and has support for both ElasticSearch 5.x and 2.x depending on your import statement. In this article, we will be hitting an ElasticSearch 2.x backend.
Continue reading “ELK: Connecting to ElasticSearch with a Go client”
The open-source Zabbix monitoring solution has a REST API that provides the ability for deep integrations with your existing monitoring, logging, and alerting systems.
This fosters development of community-driven modules like Ryan Day’s zabbix Go language package, which is an easy way to automate Zabbix tasks like creating hosts and manipulating other back end structures.
One of the nice things about the Go language is that libraries are generally statically linked into a single executable, so you only need to copy over a single executable. You don’t have to copy 3rd party jars (Java) or require an internet connection to pypi from production system (Python).
Continue reading “Zabbix: Zabbix REST API using a Go client”
The ELK stack (ElasticSearch-Logstash-Kibana), is a horizontally scalable solution with multiple tiers and points of extension and scalability.
Because so many companies have adopted the platform and tuned it for their specific use cases, it would be impossible to enumerate all the novel ways in which scalability and availability had been enhanced by load balancers, message queues, indexes on distinct physical drives, etc… So in this article I want to explore the obvious extension points, and encourage the reader to treat this as a starting point in their own design and deployment.
Continue reading “ELK: Architectural points of extension and scalability for the ELK stack”
Kibana is the end user web application that allows us to query Elasticsearch data and create dashboards that can be used for analysis and decision making.
Although Kibana can be pointed to any of the nodes in your Elasticsearch cluster, the best way to distribute requests across the nodes is to use a non-master, non-data Client node. Client nodes have the following properties set in elasticsearch.yml:
Continue reading “ELK: Pointing Kibana to a Client Node”