[NetScaler] Squid may record "error:transaction-end-before-headers" when be the service of LB

[NetScaler] Squid may record "error:transaction-end-before-headers" when be the service of LB

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Article ID: CTX691274

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Description

In a NetScaler Load Balancing deployment, you may have a Squild proxy server configured as a NetScaler LB Service. And you may observe "error:transaction-end-before-headers" recorded on Squid server. The error apears periodically with several seconds interval. Log sample:

Timestamp xxxx (squid-1)[269825]: xxxxxxxxx 0 xx.xx.xx.xx NONE/000 0 NONE error:transaction-end-before-headers - HIER_NONE/- -

Environment

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Resolution

Change service monitor to HTTP-ECV type can resolve the issue. Refer to: CTX120921 - How to Configure HTTP-ECV Health Monitor for Internet Proxy Servers

For workaround, you can configure Squid log ACL to ignore these logs. Refer to: RHEL KB: Squid access.log is being filled with "error:transaction-end-before-headers" errors

Problem Cause

By default, NetScaler uses TCP probe to monitor Squid server's health. Connection will be closed after 3-way handshake. But Squid expects HTTP data after connection. If there is no HTTP data, squid can record the error in its logs. 

Issue/Introduction

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