# Before Install You MUST set up your environment according to the steps below before installing Fluentd. Failing to do so will be the cause of many unnecessary problems. ## Set Up NTP It's HIGHLY recommended that you set up NTP daemon (e.g. [*chrony*](https://chrony.tuxfamily.org/), *ntpd*, etc) on the node to have accurate current timestamp. This is crucial for the production-grade logging services. For AWS (Amazon Web Services) users we recommend to use Amazon Time Sync Service, AWS hosted NTP server. Please check [AWS EC2: Setting the Time for Your Linux Instance](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/set-time.html). ## Increase Max # of File Descriptors Please increase the maximum number of file descriptors. You can check the current number using the `ulimit -n` command. ``` $ ulimit -n 65535 ``` If your console shows `1024`, it is insufficient. Please add following lines to your `/etc/security/limits.conf` file and reboot your machine. ``` root soft nofile 65536 root hard nofile 65536 * soft nofile 65536 * hard nofile 65536 ``` This `65536` is safer value for large deployment. The required number of file descriptors depends on your fluentd plugins and setting. Here are the estimation examples: * in\_tail: The number of watching files * in\_forward: The number of incoming access * buf\_file: The number of buffer chunks. It is configured via [buffer parameters](broken://pages/-LS28ivnCJOyvnLzfHdM) * output: The used file descriptors are less than others. Temporary file for upload, connection pooling in the client library, etc ## Optimize Network Kernel Parameters For high load environments consisting of many Fluentd instances, please add these parameters to your `/etc/sysctl.conf` file. Please either type `sysctl -p` or reboot your node to have the changes take effect. ``` net.core.somaxconn = 1024 net.core.netdev_max_backlog = 5000 net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 net.ipv4.tcp_wmem = 4096 12582912 16777216 net.ipv4.tcp_rmem = 4096 12582912 16777216 net.ipv4.tcp_max_syn_backlog = 8096 net.ipv4.tcp_slow_start_after_idle = 0 net.ipv4.tcp_tw_reuse = 1 net.ipv4.ip_local_port_range = 10240 65535 ``` These kernel options were originally taken from the presentation "[How Netflix Tunes EC2 Instances for Performance](https://www.slideshare.net/brendangregg/how-netflix-tunes-ec2-instances-for-performance)" by [Brendan Gregg](http://www.brendangregg.com/), Senior Performance Architect at AWS re:Invent 2017. If this article is incorrect or outdated, or omits critical information, please [let us know](https://github.com/fluent/fluentd-docs-gitbook/issues?state=open). [Fluentd](http://www.fluentd.org/) is a open source project under [Cloud Native Computing Foundation (CNCF)](https://cncf.io/). All components are available under the Apache 2 License. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.fluentd.org/0.12/articles/before-install.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.