geode-docs/getting_started/system_requirements/host_machine.html.md.erb - geode - Git at Google

 ---
 title:  Host Machine Requirements
 ---

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 Host machines must meet a set of requirements for <%=vars.product_name_long%>.

 <a id="system_requirements__section_1E1F206FBC8B4A898A449E0699907A7A"></a>
 Each machine that will run <%=vars.product_name_long%> must meet the following requirements:

 -   Java SE Development Kit <%=vars.min_java_version%> with update <%=vars.min_java_update%> or a more recent version <%=vars.min_java_version%> update.  The same versions are supported with OpenJDK.
 -   A system clock set to the correct time and a time synchronization service such as Network Time Protocol (NTP). Correct time stamps permit the following activities:
     -   Logs that are useful for troubleshooting. Synchronized time stamps ensure that log messages from different hosts can be merged to reproduce an accurate chronological history of a distributed run.
     -   Aggregate product-level and application-level time statistics.
     -   Accurate monitoring of the Geode system with scripts and other tools that read the system statistics and log files.
 -   The host name and host files are properly configured for the machine. The host name and host file configuration can affect `gfsh` and Pulse functionality.
 -   Disable TCP SYN cookies. Most default Linux installations use SYN cookies to protect the
 system against malicious attacks that flood TCP SYN packets, but this feature
 is not compatible with stable and busy <%=vars.product_name%> clusters.
 Security implementations should instead seek to prevent attacks by placing <%=vars.product_name%>
 server clusters behind advanced firewall protection.

     To disable SYN cookies permanently:
     1. Edit the `/etc/sysctl.conf` file to include the following line:

         ``` pre
         net.ipv4.tcp_syncookies = 0
         ```
         Setting this value to zero disables SYN cookies.
     2. Reload `sysctl.conf`:

         ``` pre
         sysctl -p
         ```

     See [Disabling TCP SYN Cookies](../../managing/monitor_tune/disabling_tcp_syn_cookies.html) for details.
	---
	title: Host Machine Requirements
	---

	<!--
	Licensed to the Apache Software Foundation (ASF) under one or more
	contributor license agreements. See the NOTICE file distributed with
	this work for additional information regarding copyright ownership.
	The ASF licenses this file to You under the Apache License, Version 2.0
	(the "License"); you may not use this file except in compliance with
	the License. You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
	-->

	Host machines must meet a set of requirements for <%=vars.product_name_long%>.

	<a id="system_requirements__section_1E1F206FBC8B4A898A449E0699907A7A"></a>
	Each machine that will run <%=vars.product_name_long%> must meet the following requirements:

	- Java SE Development Kit <%=vars.min_java_version%> with update <%=vars.min_java_update%> or a more recent version <%=vars.min_java_version%> update. The same versions are supported with OpenJDK.
	- A system clock set to the correct time and a time synchronization service such as Network Time Protocol (NTP). Correct time stamps permit the following activities:
	- Logs that are useful for troubleshooting. Synchronized time stamps ensure that log messages from different hosts can be merged to reproduce an accurate chronological history of a distributed run.
	- Aggregate product-level and application-level time statistics.
	- Accurate monitoring of the Geode system with scripts and other tools that read the system statistics and log files.
	- The host name and host files are properly configured for the machine. The host name and host file configuration can affect `gfsh` and Pulse functionality.
	- Disable TCP SYN cookies. Most default Linux installations use SYN cookies to protect the
	system against malicious attacks that flood TCP SYN packets, but this feature
	is not compatible with stable and busy <%=vars.product_name%> clusters.
	Security implementations should instead seek to prevent attacks by placing <%=vars.product_name%>
	server clusters behind advanced firewall protection.

	To disable SYN cookies permanently:
	1. Edit the `/etc/sysctl.conf` file to include the following line:

	``` pre
	net.ipv4.tcp_syncookies = 0
	```
	Setting this value to zero disables SYN cookies.
	2. Reload `sysctl.conf`:

	``` pre
	sysctl -p
	```

	See [Disabling TCP SYN Cookies](../../managing/monitor_tune/disabling_tcp_syn_cookies.html) for details.