Changes in Varnish 7.4¶
For information about updating your current Varnish deployment to the new version, see Upgrading to Varnish 7.4.
A more detailed and technical account of changes in Varnish, with links to issues that have been fixed and pull requests that have been merged, may be found in the change log.
varnishd¶
HTTP/2 header field validation is now more strict with respect to allowed characters.
The VCL-steps manual page has been added to document the VCL state machines.
VCL Tracing¶
VCL tracing now needs to be explicitly activated by setting the
req.trace or bereq.trace VCL variables, which are initialized
from the feature +trace flag. Only if the trace variables are set
will VCL_trace log records be generated.
Consequently, VCL_trace has been removed from the default
vsl_mask, so any trace records will be emitted by
default. vsl_mask can still be used to filter VCL_trace
records.
To trace vcl_init {} and vcl_fini {}, set the feature
+trace flag while the vcl is loaded/discarded.
Parameters¶
The startup_timeout parameter now specifically replaces
cli_timeout for the initial startup only.
Changes to VCL¶
The Content-Length and Transfer-Encoding headers are now
protected. For the common use case of unset
(be)req.http.Content-Length to dismiss a body, unset
(be)req.body should be used.
varnishlog¶
Object creation failures by the selected storage engine are now logged
under the Error tag as Failed to create object from %s
%s.
varnishadm¶
Tabulation of the vcl.list CLI output has been modified slightly.
varnishstat¶
The counter MAIN.http1_iovs_flush has been added to track the
number of premature writev() calls due to an insufficient number
of IO vectors. This number is configured through the http1_iovs
parameter for client connections and implicitly defined by the amount
of free workspace for backend connections.
varnishtest¶
The basename of the test directory is now available as the vtcid
macro to serve as a unique string across concurrently running tests.
The varnishd_args_prepend and varnishd_args_append macros have
been added to allow addition of arguments to varnishd invocations
before and after those added by varnishtest by default.
User-Agent request and Server response headers are now created
by default, containing the respective client and server name. The
txreq -nouseragent and txresp -noserver options disable
addition of these headers.